| 1 | Latin | inpugno | Alternative form of impugnō |
| 2 | Latin | impugno | I attack, fight against; I impugn, assail |
| 3 | Latin | in- | un-, non-, not; in, within, inside |
| 4 | Latin | in | in, at, on, upon, from; within, while in; into,... |
| 5 | Old Latin | en | in |
| 6 | Proto-Italic | en | in |
| 7 | Proto-Indo-European | h₁én | in |