| 1 | English | inefficient | Not efficient; not producing the effect intended... |
| 2 | English | in- | in, into, towards, within; in, into; Used with... |
| 3 | Middle English | in- | — |
| 4 | Old English | in- | in, into; on, upon; internal, positioned on the... |
| 5 | Old English | in | in; Alternative form of inn |
| 6 | Proto-West Germanic | *in | — |
| 7 | Proto-Germanic | in | in; into |
| 8 | Proto-Indo-European | én | in |