in-

{{11}}in- (1) prefix meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant), from L. in- "not," cognate with Gk. an-, O.E. un-, from PIE *ne "not" (see UN- (Cf. un-) (1)).

{{12}}in- (2) element meaning "into, in, on, upon" (also im-, il-, ir- by assimilation of -n- with following consonant), from L. in- "in" (see IN (Cf. in)). In O.Fr. this often became en-, which usually was respelled in English to conform with Latin, but not always, which accounts for pairs like enquire/inquire. There was a native form, which in W.Saxon usually appeared as on- (Cf. O.E. onliehtan "to enlighten"), and some verbs survived into M.E. (Cf. inwrite "to inscribe"), but all now seem to be extinct. Not related to IN- (Cf. in-) (1) "not," which also was a common prefix in Latin: to the Romans impressus could mean "pressed" or "unpressed."