Online Etymology Dictionary

go over (v.): "to review point by point," 1580s.
go south (v.): "vanish, abscond," 1920s, American English, probably from mid-19c. notion of disappearing south to Mexico or Texas to escape pursuit or responsibility, reinforced by Native American belief (attested in colonial writing mid-18c.) that the soul journeys south after death.
go through (v.): "to execute, carry to completion" (a plan, etc., often with with), 1560s. Meaning "to examine" is 1660s; "to endure" is by 1712; "to wear out" by 1959.
go together (v.): "be courting," by 1899.
go west (v.): 19c. British idiom for "die, be killed" (popularized during World War I), "probably from thieves' slang, wherein to go west meant to go to Tyburn, hence to be hanged, though the phrase has indubitably been influenced by the setting of the sun in the west." [Partridge]
go-between (n.): 1590s, from go (v.) + between. Verbal phrase meaning "act as a mediator" is recorded from 1540s.
go-cart (n.): also gocart, 1670s, originally "a litter, sedan chair;" also "an infant's walker" (1680s), from go + cart (n.). The modern form go-kart (1959) was coined in reference to a kind of miniature racing car with a frame body and a two-stoke engine.
go-getter (n.): 1910, American English, from go + agent noun from get (v.). Goer, with essentially the same meaning, is attested from late 14c.
go-go (adj.): 1964, "fashionable," from slang the go "the rage" (1962); see go. First appearance of go-go dancer is from 1965.
go-it-alone: adjective phrase, attested by 1953 (in reference to U.S. foreign policy proposals), from American English verbal phrase attested by 1842.
go-round (n.): "act of going around," originally especially "a merry-go-round," 1886, from go (v.) + round (adv.). Figurative sense of "argument, bout, fight," etc. is from 1891.
go-to-meeting (adj.): "suitable for use in a church or on Sundays," 1790, especially of clothes but the earliest recorded reference is to music.
Goa: former Portuguese colony in India, from local goe mat "fertile land."
goad (n.): Old English gad "point, spearhead, arrowhead," from Proto-Germanic *gaido (cf. Lombardic gaida "spear"), from PIE *ghei- (cf. Sanskrit hetih "missile, projectile," himsati "he injures;" Avestan zaena- "weapon;" Greek khaios "shepherd's staff;" Old English gar "spear;" Old Irish gae "spear"). Figurative use is since 16c., probably from the Bible.
goad (v.): 1570s, from goad (n.); earliest use is figurative. Related: Goaded; goading.
goal (n.): 1530s, "end point of a race," of uncertain origin. The noun gol appears once before this, in a poem from early 14c. and with an apparent sense of "boundary, limit." Perhaps from Old English *gal "obstacle, barrier," a word implied by gælan "to hinder." Or from Old French gaule "a pole," from Germanic; or a figurative use of Middle English gale "a way, course." Sports sense of "place where the ball is put to score" is attested from 1540s. Figurative sense of "object of an effort" is from 1540s.
goalie (n.): 1921, from goal + -ie. Probably a shortening of goal-tender (1909), which tends to be the term used in ice hockey, as opposed to goal-keeper (1650s).
goalless (adj.): 1835, of journeys, etc., from goal + -less. By 1903 of sports matches where nobody scores. Related: Goallessly; goallessness.
goat (n.): Old English gat "she-goat," from Proto-Germanic *gaitaz (cf. Old Saxon get, Old Norse geit, Danish gjed, Middle Dutch gheet, Dutch geit, Old High German geiz, German Geiß, Gothic gaits "goat"), from PIE *ghaidos "young goat," also "play" (cf. Latin hædus "kid").

The word for "male goat" in Old English was bucca (see buck (n.)) until late 1300s shift to he-goat, she-goat (Nanny goat is 18c., billy goat 19c.). Meaning "licentious man" is attested from 1670s. To get (someone's) goat is from 1910, perhaps with notion of "to steal a goat mascot from a racehorse," or from French prendre sa chèvre "take one's source of milk."
goatee (n.): 1844 (as goaty), from goaty (adj.). So called from its resemblance to a male goat's chin hairs.
goatherd (n.): early 13c. (as a surname), from goat + herd (n.).
goatish (adj.): 1520s, from goat + -ish. Related: Goatishly; goatishness.
goatskin (n.): late 14c., from goat + skin (n.).
goaty (adj.): "goat-like," c.1600, from goat + -y (2).
gob (n.): "a mouthful, lump," late 14c., probably from Old French gobe "mouthful, lump," related to gober "gulp, swallow down," probably from Gaulish *gobbo- (cf. Irish gob "mouth," Gaelic gob "beak"). This Celtic source also seems to be root of gob "mouth" (mid-16c.), which is the first element in gob-stopper "a kind of large hard candy" (1928).
gobbet (n.): late 13c., "a fragment," from Old French gobet "piece, mouthful," diminutive of gobe (see gob).
gobble (v.1): "eat greedily," c.1600, probably partly echoic, partly frequentative of gob, via gobben "drink something greedily." Related: Gobbled; gobbling.
gobble (v.2): "make a turkey noise," 1670s, probably imitative, perhaps influenced by gobble (1) or gargle. As a noun from 1781.
gobbledygook (n.): also gobbledegook, "the overinvolved, pompous talk of officialdom" [Klein], 1944, American English, first used by U.S. Rep. Maury Maverick, D.-Texas, (1895-1954), a grandson of the original maverick and chairman of U.S. Smaller War Plants Corporation during World War II. First used in a memo dated March 30, 1944, banning "gobbledygook language" and mock-threateaning, "anyone using the words activation or implementation will be shot." Maverick said he made up the word in imitation of turkey noise. Another word for it, coined about the same time, was bafflegab (1952).
gobbler (n.): 1737, "turkey cock," agent noun from gobble (v.2). As "one who eats greedily" 1755, from gobble (v.1).
Gobi: desert in central Asia, from Mongolian gobi "desert." Gobi Desert is thus a pleonasm (see Sahara).
goblet (n.): late 14c., from Old French gobelet "goblet, cup," diminutive of gobel "cup," probably related to gobe "gulp down" (see gob).
goblin (n.): early 14c., "a devil, incubus, fairy," from Old French gobelin (12c., as Medieval Latin Gobelinus, the name of a spirit haunting the region of Evreux, in chronicle of Ordericus Vitalis), of uncertain origin, perhaps related to German kobold (see cobalt), or from Medieval Latin cabalus, from Greek kobalos "rogue, knave," kobaloi "wicked spirits invoked by rogues," of unknown origin. Another suggestion is that it is a diminutive of the proper name Gobel.
Though French gobelin was not recorded until almost 250 years after appearance of the English term, it is mentioned in the Medieval Latin text of the 1100's, and few people who believed in folk magic used Medieval Latin. [Barnhart]
gobo: 1930, American English, Hollywood movie set slang, of unknown origin, perhaps somehow from go-between.
gobsmacked (adj.): by 1990, U.K. slang, from gob "mouth" + past participle of smack.
goby (n.): kind of fish, 1769, from Latin gobius, from Greek gobios, name of a type of small fish, of unknown origin.
god (n.): Old English god "supreme being, deity; the Christian God; image of a god; godlike person," from Proto-Germanic *guthan (cf. Old Saxon, Old Frisian, Dutch god, Old High German got, German Gott, Old Norse guð, Gothic guþ), from PIE *ghut- "that which is invoked" (cf. Old Church Slavonic zovo "to call," Sanskrit huta- "invoked," an epithet of Indra), from root *gheu(e)- "to call, invoke."

But some trace it to PIE *ghu-to- "poured," from root *gheu- "to pour, pour a libation" (source of Greek khein "to pour," also in the phrase khute gaia "poured earth," referring to a burial mound; see found (v.2)). "Given the Greek facts, the Germanic form may have referred in the first instance to the spirit immanent in a burial mound" [Watkins]. Cf. also Zeus.

Not related to good. Originally a neuter noun in Germanic, the gender shifted to masculine after the coming of Christianity. Old English god probably was closer in sense to Latin numen. A better word to translate deus might have been Proto-Germanic *ansuz, but this was used only of the highest deities in the Germanic religion, and not of foreign gods, and it was never used of the Christian God. It survives in English mainly in the personal names beginning in Os-.
I want my lawyer, my tailor, my servants, even my wife to believe in God, because it means that I shall be cheated and robbed and cuckolded less often. ... If God did not exist, it would be necessary to invent him. [Voltaire]
God bless you after someone sneezes is credited to St. Gregory the Great, but the pagan Romans (Absit omen) and Greeks had similar customs.
god-fearing (adj.): 1759, from God + fearing (see fear).
godawful (adj.): "terrible," 1878, from God + awful. The God might be an intensifier or the whole might be from the frequent God's awful (vengeance, judgment, etc.) in religious literature.
godchild (n.): "child one sponsors at baptism," c.1200, from God + child.
goddamn: late 14c., from god + damn.
Mais, fussent-ils [les anglais] cent mille Goddem de plus qu'a present, ils n'auront pas ce royaume. [Joan of Arc, 1431, quoted in Prosper de Barante's "Histoire des ducs de Bourgogne"]
Goddammes was the nickname given by Puritans to Cavaliers, in consequence of the latter's supposed frequent employment of that oath.
goddaughter (n.): girl one sponsors at her baptism, mid-13c., from god + daughter.
goddess (n.): mid-14c., from god + fem. suffix -esse (see -ess). Of mortal women, by 1570s.
godfather (n.): man who sponsors one at baptism, late 12c., from god + father (n.). In the Mafia sense, from 1963. Popularized by Mario Puzo's novel (1969) and the movie based on it (1972).
godforsaken (adj.): 1816, from God + forsaken.
Godfrey: masc. proper name, from Old French Godefrei (Modern French Godefroi), from Old High German Godafrid (German Gottfried), literally "the peace of God," from Old High German got "God" (see god) + fridu "peace" (see free). In early 20c., the name sometimes was used as a slang euphemism for "God."
godhead (n.): c.1200, from god + Middle English -hede, cognate with -hood and German -heit. Along with maidenhead, this is the sole survival of this form of the suffix. Old English had godhad "divine nature."
Godiva: d.1067, Lady of Coventry and wife of Leofric, Earl of Mercia. Legend first recorded 100 years after her death, by Roger of Wendover. "Peeping Tom" aspect added by 1659.
godless (adj.): 1520s, from god + -less. Related: Godlessness. Phrase godless communism attested by 1851.
godlike (adj.): 1510s, from god + -like.