| 1 | English | difficult | Hard, not easy, requiring much effort; Hard to... |
| 2 | Middle English | difficult | — |
| 3 | Middle English | difficulte | — |
| 4 | Middle French | difficulté | difficulty |
| 5 | Old French | difficulté | difficulty |
| 6 | Latin | difficultas | difficulty, distress, trouble, hardship |
| 7 | Latin | difficilis | difficult, hard, troublesome; obstinate,... |
| 8 | Latin | facilis | that may or can be done or made; easy, facile |
| 9 | Latin | faciō | — |
| 10 | Latin | -torium | nominative neuter singular of -tōrius; accusative... |
| 11 | Latin | -tōrius | — |
| 12 | Latin | -tor | -er |
| 13 | Proto-Italic | -tōr | — |
| 14 | Proto-Indo-European | -tōr | Derives agent nouns from verbs, denoting someone... |
| 15 | Proto-Indo-European | -tor-s | — |