prefix (also il-, im-, ir-) added to:
1 adjectives, meaning 'not' (inedible; insane).
2 nouns, meaning 'without, lacking' (inaction).
Etymology: L
2.
prefix (also il- before l, im- before b, m, p, ir- before r) in, on, into, towards, within (induce; influx; insight; intrude).
Etymology: IN, or from or after L in IN prep.
Useful english dictionary. 2012.