"not accomplished," c. 1300, from un- (1) "not" + done. The same word meaning "destroyed" is recorded from mid-14c., past-participle adjective from undo.
Entries linking to undone
un- 1
prefix of negation, Old English un-, from Proto-Germanic *un- (source also of Old Saxon, Old Frisian, Old High German, German un-, Gothic un-, Dutch on-), from PIE *n- (source of Sanskrit a-, an- "not," Greek a-, an-, Old Irish an-, Latin in-), combining form of PIE root *ne- "not." Often euphemistic (such as untruth for "lie").
The most prolific of English prefixes, freely and widely used in Old English, where it forms more than 1,000 compounds. It underwent a mass extinction in early Middle English, but emerged with renewed vigor 16c. to form compounds with native and imported words. It disputes with Latin-derived cognate in- (1) the right to form the negation of certain words (indigestable/undigestable, etc.), and though both might be deployed in cooperation to indicate shades of meaning (unfamous/infamous), typically they are not.
It also makes words from phrases (such as uncalled-for, c. 1600; undreamed-of, 1630s; uncome-at-able, 1690s; unputdownable, 1947, of a book; un-in-one-breath-utterable, Ben Jonson; etc., but the habit is not restricted to un-; such as put-up-able-with, 1812). As a prefix in telegramese to replace not and save the cost of a word, it is attested by 1936.
done
past participle of do (v.); from Old English past participle gedon (a vestige of the prefix is in ado). As a past-participle adjective meaning "completed, finished, performed, accomplished" from early 15c. As a word of acceptance of a deal or wager, 1590s.
U.S. Southern use of done in phrases such as done gone (or "Octopots done got Albert!") is attested by 1827, according to OED: "a perfective auxiliary or with adverbial force in the sense 'already; completely.' " Century Dictionary writes that it was "originally causal after have or had, followed by an object infinitive ; in present use the have or had is often omitted and the infinitive turned into a preterit, leaving done as a mere preterit sign" and calls it "a characteristic of negro idiom."
To be done in "exhausted" is by 1917. Slang done for "doomed" is by 1803 (colloquial do for "ruin, damage" is from 1740). To have done it "to have been very foolish, made a mess of things" is from 1837.
undo v.
Old English undon "to unfasten and open" (a window or door), "to unfasten by releasing from a fixed position; to cancel, discharge, abrogate, reverse what has been done, put back in a former condition; bring to ruin, destroy," from un- (2) "opposite of" + do (v.). Related: Undone; undoing.