liftoff n.

c. 1200, "elevate in rank or dignity, exalt;" c. 1300, "to raise from the ground or other surface, pick up; erect, set in place," also intransitive, "to rise in waves;" early 14c., "remove (someone or something) from its place," from Old Norse lypta "to raise" (Scandinavian -pt- pronounced like -ft-), from Proto-Germanic *luftijan (source also of Middle Low German lüchten, Dutch lichten, German lüften "to lift"), a Proto-Germanic verb from the general Germanic noun for "air, sky, upper regions, atmosphere" (see loft (n.)), giving the verb an etymological sense of "to move up into the air."

Intransitive sense of "to rise, to seem to rise" (of clouds, fogs, etc.) is from 1834. Figurative sense of "to encourage" (with up) is mid-15c. The meaning "steal, take up dishonestly" (as in shoplift) is 1520s. Surgical sense of "to raise" (a person's face) is from 1921. Middle English also had a verb liften (c. 1400). Related: Lifted; lifting.

by c. 1200 as an emphatic form of Old English of (see of), employed in the adverbial use of that word. The prepositional meaning "away from" and the adjectival sense of "farther" were not firmly fixed in this variant until 17c., but once they were they left the original of with the transferred and weakened senses of the word. Meaning "not working" is from 1861.

Off the cuff "extemporaneously, without preparation" (1938) is from the notion of speaking from notes written in haste on one's shirt cuffs. In reference to clothing, off the rack (adj.) "not tailored, not made to individual requirements, ready-made" is by 1963, on the notion of buying it from the rack of a clothing store; off the record "not to be publicly disclosed" is from 1933; off the wall "crazy" is 1968, probably from the notion of a lunatic "bouncing off the walls" or else in reference to carom shots in squash, handball, etc.