| 1 | English | conscientious | Thorough, careful, or vigilant in one’s task... |
| 2 | Middle French | conscientieux | conscientious |
| 3 | Latin | cōnscientiōsus | — |
| 4 | Latin | cōnscientia | — |
| 5 | Latin | conscire | present active infinitive of cōnsciō; to know, to... |
| 6 | Latin | com- | allomorph of con- |
| 7 | Latin | con- | Used in compounds to indicate a being or bringing... |
| 8 | Latin | cum | with, along with; at; -fold |
| 9 | Old Latin | com | Alternative form of cum |
| 10 | Proto-Italic | kom | with, along, at |
| 11 | Proto-Indo-European | ḱóm | beside, near, by, with |
| 12 | Proto-Indo-European | ḱe | Deictic particle, here; Post-positional... |
| 13 | Middle English | kyt | — |
| 14 | German | kitt | — |
| 15 | Old High German | kuti | — |
| 16 | Proto-West Germanic | kwidu | gum, resin |
| 17 | Proto-Germanic | kweduz | resin |
| 18 | Proto-Indo-European | gʷet- | resin, gum; to say, speak |