unkindly (adv.)

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.

c. 1200, cundeliche, "natively, congenitally; according to nature," from Old English gecyndelice "naturally;" see kind (adj.) -ly (2). From mid-13c. as "pleasantly, gladly, with kind feelings, in a kind manner." Also in Middle English, "by birth or descent; in the approved manner, properly" (late 14c.).

c. 1200, cundelich, "natural, right, lawful," from Old English gecyndelic "natural, innate; in accordance with the laws or processes of nature, suitable, lawful" (of birth, etc.); see kind (adj.) + -ly (1). From late 14c. as "pleasant, agreeable;" from 1560s as "full of loving courtesy." Related: Kindliness. The Old English word also meant "pertaining to generation," hence cyndlim "womb," in plural "genitalia," literally "kind-limb."