| 1 | English | suspicious | Arousing suspicion; Distrustful or tending to... |
| 2 | Old French | sospecious | — |
| 3 | Latin | suspiciosus | suspicious |
| 4 | Latin | suspiciō | — |
| 5 | Latin | suspicere | second-person singular present active subjunctive... |
| 6 | Latin | specere | present active infinitive of speciō;... |
| 7 | Latin | specio | I observe, watch, look at |
| 8 | Proto-Italic | spekjō | to observe, to see |
| 9 | Proto-Indo-European | spéḱyeti | to be looking at, to keep looking at |
| 10 | Proto-Indo-European | speḱ- | to see, to look, to observe |