Online Etymology Dictionary

dragon: early 13c., from O.Fr. dragon, from L. draconem (nom. draco) "serpent, dragon," from Gk. drakon (gen. drakontos) "serpent, seafish," from drak-, strong aorist stem of derkesthai "to see clearly." But perhaps the lit. sense is "the one with the (deadly) glance." The young are dragonets (14c.). Obsolete drake "dragon" is an older borrowing of the same word. Used in the Bible to translate Heb. tannin "a great sea-monster," and tan, a desert mammal now believed to be the jackal.
dragonfly: 1620s, from dragon + fly (n.).
dragoon: 1622, from Fr. dragon "carbine, musket," because the guns the soldiers carried "breathed fire" like a dragon. The verb is from 1689, lit. "to force by the agency of dragoons" (which were used by the Fr. kings to persecute Protestants).
drake (2): archaic for "dragon," from O.E. draca, from P.Gmc. *drako (see dragon).
oolong: "dark variety of Chinese tea," 1852, from Chinese wu-lung, lit. "black dragon."
Komodo dragon: 1927, named for Indonesian island of Komodo, where it lives.
draconian: 1876 (earlier Draconic, 1680), from Draco, Gk. statesman who laid down a code of laws for Athens 621 B.C.E. that mandated death as punishment for minor crimes. His name seems to mean lit. "sharp-sighted" (see dragon).
pendragon: "Welsh warlord" (mainly known now in Arthurian Uther Pendragon), 1470, title of a chief leader in war of ancient Britain or Wales, from pen "head" + dragon (q.v.), which figured on the standard of a cohort.
rankle: c.1320, from O.Fr. rancler, from draoncle "abscess, festering sore," from L. dracunculus "little snake," dim. of draco (gen. draconis) "serpent, dragon." The notion is of an ulcer caused by a snake's bite.
leviathan: 1382, from L.L. leviathan, from Heb. livyathan "dragon, serpent, huge sea animal," of unknown origin, perhaps related to liwyah "wreath," from base l-w-h- "to wind, turn, twist."
Hesperus: late 14c., poetic for "the evening star," from Gk. hesperos (aster) "western (star)." Hence also Hesperides (c.1590), from Gk., "daughters of the West," any of the nymphs, daughters of Hesperus, who guarded, with the aid of a dragon, the garden in which the golden apples grew, in the Isles of the Blest, at the western extremity of the earth.
wyvern: 1610, formed (with excrescent -n) from M.E. wyver (c.1300), from Anglo-Fr. wivre, from O.N.Fr. form of O.Fr. guivre "snake," from L. vipera "viper" (see viper). In heraldry, a winged dragon with eagle's feet and a serpent's barbed tail.
George: male personal name, from L. Georgius, from Gk. Georgios "husbandman, farmer," from ge "earth" + ergon "work" (see urge (v.)). The name introduced in England by the Crusaders (a vision of St. George played a key role in the First Crusade), but not common until after the Hanoverian succession (18c.); so also Georgian (1855) in reference to the reigns of the first four king Georges (1714-1830). St. George began to be recognized as patron of England in time of Edward III, perhaps because of his association with the Order of the Garter (see garter). His feast day, April 23, was made a holiday in 1222. The legend of his combat with the dragon is first found in "Legenda Aurea" (13c.). The exclamation by (St.) George! is recorded from 1598.
schmuck: "contemptible person," 1892, from E.Yiddish shmok, lit. "penis," from Old Pol. smok "grass snake, dragon." Not the same word as Ger. schmuck "jewelry, adornments," which is related to Low Ger. smuck "supple, tidy, trim, elegant," and related to O.N. smjuga "slip, step through" (see smock). In Jewish homes, the word was "regarded as so vulgar as to be taboo" [Leo Rosten, "The Joys of Yiddish," 1968] and Lenny Bruce wrote that saying it on stage got him arrested on the West Coast "by a Yiddish undercover agent who had been placed in the club several nights running to determine if my use of Yiddish terms was a cover for profanity." Euphemized as schmoe, which was the source of Al Capp's cartoon strip creature the schmoo.
angel: 14c. fusion of O.E. engel (with hard -g-) and O.Fr. angele, both from L. angelus, from Gk. angelos "messenger," possibly related to angaros "mounted courier," both from an unknown Oriental source, perhaps related to Skt. ajira- "swift." Used in Scriptural translations for Heb. mal'akh (yehowah) "messenger (of Jehovah)," from base l-'-k "to send." The medieval gold coin (a new issue of the noble, first struck 1465 by Edward VI) was so called for the image of archangel Michael slaying the dragon, which was stamped on it. It was the coin given to patients who had been "touched" for the King's Evil. Angel food cake is from 1881; angel dust "phencyclidine" is from 1968. Angel-fish (1668) was so called for its "wings."
worm: O.E. wurm, variant of wyrm "serpent, dragon," also in later O.E. "earthworm," from P.Gmc. *wurmiz (cf. O.S., O.H.G., Ger. wurm, O.Fris., Du. worm, O.N. ormr, Goth. waurms "serpent, worm"), from PIE *wrmi-/*wrmo- "worm" (cf. Gk. rhomos, L. vermis "worm," O.Rus. vermie "insects," Lith. varmas "insect, gnat"), possibly from base *wer- "turn" (see versus). The ancient category of these was much more extensive than the modern, scientific, one and included serpents, scorpions, maggots, and the supposed causes of certain diseases. In Eng., the -o- was a scribal substitution to avoid confusion of -u- and -r- (as also in some, come, monk etc.). As an insult meaning "abject, miserable person" it dates from O.E. The verb meaning "to move like a worm" is recorded from 1610, in fig. senses (attested from 1627) suggesting patient, sinuous progress.
spook (n.): 1801, from Du. spook, from M.Du. spooc "spook, ghost," from a common Gmc. source (cf. Ger. Spuk "ghost, apparition," M.L.G. spok "spook," Swed. spok "scarecrow, Norw. spjok "ghost, specter," Dan. spøg "joke"), of unknown origin. Possible outside connections include Lettish spigana "dragon, witch," spiganis "will o' the wisp," Lith. spingu, spingeti "to shine," O.Pruss. spanksti "spark." Meaning "undercover agent" is attested from 1942. The verb is first recorded 1867 in sense of "to walk or act like a ghost;" meaning "to unnerve" is from 1935. The derogatory racial sense of "black person" is attested from 1940s, perhaps from notion of dark skin being difficult to see at night. Black pilots trained at Tuskegee Institute during World War II called themselves the Spookwaffe. Spooky is from 1854.