offspring n.

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.

Old English springan "to leap, burst forth, fly up; spread, grow," (class III strong verb; past tense sprang, past participle sprungen), from Proto-Germanic *sprengan (source also of Old Norse, Old Frisian springa, Middle Dutch springhen, Dutch Related: springen, Old Saxon and Old High German springan, German springen), from PIE *sprengh-, nasalized form of root *spergh- "to move, hasten, spring" (source also of Sanskrit sprhayati "desires eagerly," Greek sperkhesthai "to hurry").

In Middle English, it took on the role of causal sprenge, from Old English sprengan (as still in to spring a trap, etc.). Meaning "to cause to work or open," by or as by a spring mechanism, is from 1828. Meaning "to announce suddenly" (usually with on) is from 1876. Meaning "to release" (from imprisonment) is from 1900. Slang meaning "to pay" (for a treat, etc.) is recorded from 1906.