unattended 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.

c. 1300, "be subject to" (obsolete); early 14c., "direct one's mind or energies" (archaic), from Old French atendre "to expect, wait for, pay attention" (12c., Modern French attendre) and directly from Latin attendere "give heed to," literally "to stretch toward," from ad "to, toward" (see ad-) + tendere "stretch" (from PIE root *ten- "to stretch"). The notion is of "stretching" one's mind toward something.

The sense of "take care of, wait upon" is from mid-14c.; that of "endeavor to do" is from c. 1400. The meaning "to pay attention" is from early 15c.; that of "accompany and render service to" (someone) is from mid-15c., as is that of "be in attendance." The meaning "to accompany or follow as a consequent" is from 1610s. Related: Attended; attending.