| 1 | English | intensive | Thorough; to a great degree; with intensity;... |
| 2 | Middle French | intensif | — |
| 3 | Medieval Latin | intensivus | intensive |
| 4 | Latin | intendere | third-person plural perfect active indicative of... |
| 5 | Latin | intendo | I stretch out; I strain; I turn my attention to,... |
| 6 | Latin | in- | un-, non-, not; in, within, inside |
| 7 | Latin | in | in, at, on, upon, from; within, while in; into,... |
| 8 | Old Latin | en | in |
| 9 | Proto-Italic | en | in |
| 10 | Proto-Indo-European | h₁én | in |