| 1 | English | radioactive | Exhibiting radioactivity; Dangerous and... |
| 2 | French | radioactif | radioactive |
| 3 | French | actif | active; asset; top |
| 4 | Old French | actif | active |
| 5 | Latin | āctīvus | — |
| 6 | Ancient Greek | ἐνεργητικός | Able to act on; acting on; Active; In the active... |
| 7 | Ancient Greek | ἐνεργέω | to be in action or activity, to operate; to... |
| 8 | Ancient Greek | ἐνεργός | at work, active |
| 9 | Ancient Greek | ἐν- | in, within; on |
| 10 | Ancient Greek | ἐν | in, on, at; among; in, at, or during the time of |
| 11 | Ancient Greek | δέρμα | skin, hide |
| 12 | Ancient Greek | γλυφή | carving, carved work; hole cut |
| 13 | Ancient Greek | -ῐ́ᾱ | {{l|en|-ia}}; "suffix forming abstract feminine... |
| 14 | Proto-Indo-European | -íh₂ | — |
| 15 | Proto-Indo-European | -h₂ | Creates collective nouns, which refer to groups... |