untold (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.

Old English tellan "to reckon, calculate, number, compute; consider, think, esteem, account" (past tense tealde, past participle teald), from Proto-Germanic *taljan "to mention in order" (source also of Old Saxon tellian "tell," Old Norse telja "to count, number; to tell, say," Old Frisian tella "to count; to tell," Middle Dutch and Dutch tellen, Old Saxon talon "to count, reckon," Danish tale "to speak," Old High German zalon, German zählen "to count, reckon"), from PIE root *del- (2) "to count, reckon" (see tale).

Meaning "to narrate, announce, relate" in English is from c. 1000; that of "to make known by speech or writing, announce" is from early 12c. Sense of "to reveal or disclose" is from c. 1400; that of "to act as an informer, to 'peach' " is recorded from 1901. Meaning "to order (someone to do something)" is from 1590s. To tell (someone) off "reprimand" is from 1919.

Original sense in teller and phrase tell time. For sense evolution, compare French conter "to count," raconter "to recount;" Italian contare, Spanish contar "to count, recount, narrate;" German zählen "to count," erzählen "to recount, narrate." Klein also compares Hebrew saphar "he counted," sipper "he told."