undeveloped adj.

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.

1650s, "unroll, unfold" (a sense now obsolete), from French développer. It replaced earlier English disvelop (1590s, from French desveloper); both French words are from Old French desveloper, desvoleper, desvoloper "unwrap, unfurl, unveil; reveal the meaning of, explain," from des- "undo" (see dis-) + voloper "wrap up," which is of uncertain origin, possibly Celtic or Germanic.

The modern uses are figurative and emerged in English 18c. and after: Transitive meaning "unfold more fully, bring out the potential in" is by 1750; intransitive sense of "come gradually into existence or operation" is by 1793; that of "advance from one stage to another toward a finished state" is by 1843. The intransitive meaning "become known, come to light" is by 1864, American English.

The photographic sense "induce the chemical changes necessary to cause a latent picture or image to become visible" is from 1845; the real estate sense of "convert land to practical or profitable use" is by 1865. Related: Developed; developing.Developing as an adjective in reference to poor or primitive countries or nations that are advancing in economic, industrial, and social conditions is by 1960.