word-forming element meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant, a tendency which began in later Latin), from Latin in- "not," cognate with Greek an-, Old English un-, all from PIE root *ne- "not."
In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.
1630s, "a cutting off (mentally), abstraction, freedom from inessential elements," from French précision (16c.) and directly from Latin praecisionem (nominative praecisio) "a cutting off," in Medieval Latin "precision," noun of action from past-participle stem of praecidere "to cut off, shorten," from prae "before" (see pre-) + -cidere, combining form of caedere "to cut" (from PIE root *kae-id- "to strike"). Meaning "quality or state of being precise" is from 1740.
<a href="https://www.etymonline.com/word/imprecision">Etymology of imprecision by etymonline</a>
Harper, D. (n.d.). Etymology of imprecision. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/imprecision