Etymology
Advertisement
crack-up (n.)

1926, in reference to airplane crashes; 1936, "disintegration under stress, mental collapse" [Fitzgerald]; from the verbal phrase, from crack (v.) + up (adv.). The verbal phrase in the meaning "to break up laughing" is by 1967, transitive and intransitive. Its earliest sense was "to praise extravagantly" (as in not all it's cracked up to be).

Related entries & more 
Advertisement
crack (v.)

Old English cracian "make a sharp noise, give forth a loud, abrupt sound," from Proto-Germanic *krakojan (source also of Middle Dutch craken, Dutch kraken, German krachen); the whole group is probably ultimately imitative. Related: Cracked; cracking.

From c. 1300 as "to burst, split open" (intransitive), also transitive, "to cause to break into chinks." From 1785 as "break or crush into small pieces." Of the voice, "change tone suddenly," as that of a youth passing into manhood, c. 1600. Meaning "to open and drink" (a bottle) is from 16c.

From early 14c. as "to utter, say, speak, talk freely," especially "speak loudly or boastingly" (late 14c.). To crack a smile is from 1835, American English; to crack a joke is by 1732, probably from the "speak, say" sense. To crack the whip in the figurative sense is from 1886. Get cracking "go to work, start doing what is to be done" is by 1937.

What is a crack in English? A chat! The synonym is as perfect as possible; yet the words are subtly distinguished by a whole hemisphere of feeling. A chat, by comparison "wi' a crack," is a poor, frivolous, shallow, altogether heartless business. A crack is, indeed, only adequately to be defined as a chat with a good, kindly, human heart in it .... [P.P. Alexander, notes to "Last Leaves," Edinburgh, 1869]
Related entries & more 
crack (n.)

"a split, an opening, narrow fracture," mid-15c., earlier "a splitting sound; a fart; the sound of a trumpet" (late 14c.), probably from crack (v.).

Meaning "sharp, resounding blow" is from 1836. Meaning "rock cocaine" is first attested 1985. The superstition that it is bad luck to step on sidewalk cracks has been traced to c. 1890. Meaning "try, attempt" first attested 1830, nautical, probably a hunting metaphor, from slang sense of "fire a gun."

At their head, apart from the rest, was a black bull, who appeared to be their leader; he came roaring along, his tail straight an [sic] end, and at times tossing up the earth with his horns. I never felt such a desire to have a crack at any thing in all my life. He drew nigh the place where I was standing; I raised my beautiful Betsey to my shoulder, took deliberate aim, blazed away, and he roared, and suddenly stopped. ["A Narrative of the Life of David Crockett, Written by Himself," Philadelphia, 1834]

Adjectival meaning "top-notch, superior, excellent, first rate" (as in a crack shot) is slang from 1793, perhaps from earlier verbal sense of "do any thing with quickness or smartness" [Johnson], or from the verb in the sense of "speak boastingly" and suggesting "having qualities to be proud of" [Century Dictionary]. Grose (1796) has "THE CRACK, or ALL THE CRACK. The fashionable theme, the go." To fall or slip through the cracks figuratively, "escape notice," is by 1975. Crack-brained "demented" is attested from 1630s. The biblical crack of doom is in reference to the sound (Old English translates it as swegdynna maest).

Related entries & more 
up (n.)

"that which is up," 1530s, from up (adv.). Phrase on the up-(and-up) "honest, straightforward" first attested 1863, American English.

Related entries & more 
up (adv.)

Old English up, uppe, from Proto-Germanic *upp- "up" (source also of Old Frisian, Old Saxon up "up, upward," Old Norse upp; Danish, Dutch op; Old High German uf, German auf "up"; Gothic iup "up, upward," uf "on, upon, under;" Old High German oba, German ob "over, above, on, upon"), from PIE root *upo "under," also "up from under," hence also "over."

As a preposition, "to a higher place" from c. 1500; also "along, through" (1510s), "toward" (1590s). Often used elliptically for go up, come up, rise up, etc. Up the river "in jail" first recorded 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someone up the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retort up yours (scil. ass) is attested by late 19c.

Related entries & more 
Advertisement
up- 

prefix with various senses, from Old English up (adv.), corresponding to similar prefixes in other Germanic languages.

Related entries & more 
up (v.)

1550s, "to drive and catch (swans)," from up (adv.). Intransitive meaning "get up, rise to one's feet" (as in up and leave) is recorded from 1640s. Sense of "to move upward" is recorded from 1737. Meaning "increase" (as in up the price of oil) is attested from 1915. Compare Old English verb uppian "to rise up, swell." Related: Upped; upping. Upping block, used for mounting or dismounting horses, carriages, etc., is attested from 1796 (earlier was horsing-block, 1660s).

Related entries & more 
up (adj.)

c. 1300, "dwelling inland or upland," from up (adv.). Meaning "going up" is from 1784. From 1815 as "excited, exhilarated, happy," hence "enthusiastic, optimistic." Up-and-coming "promising" is from 1848. Musical up-tempo (adj.) is recorded from 1948.

Related entries & more 
mark-up (n.)

also markup, "amount added by a retailer to cover overhead and provide profit," 1899, from the verbal phrase in this sense (by 1870); see mark (v.) + up (adv.).

Related entries & more 
grow up (v.)

"advance toward maturity," 1530s, from grow (v.) + up (adv.). As a command to be sensible, from 1951.

Related entries & more