From Proto-Italic *-elis, from Proto-Indo-European *-elis, probably from *-lós. Cognate with Proto-Germanic *-ilaz (“-le”, adjective-forming suffix).
-ilis (neuter -ile, comparative -ilior, superlative -illimus or -ilissimus); third-declension two-termination suffix
- -ile; used to form an adjective of relation, frequently passive, to the verb or root.
- agō (“to act”) + -ilis → agilis (“that may be acted”)
- frangō (“to break”) + -ilis → fragilis (“that may be broken”)
- often attached to the perf. pass. part. stem:
- sedeō (“to sit”) + -ilis → sessilis (“of sitting”)
- pendeō (“to hang”) + -ilis → pēnsilis (“hanging”)
- flectō (“to ply”) + -ilis → flexilis (“pliable”)
- (rare) used to form an adjective from a noun or adjective stem, sometimes with passive meaning
- humus (“ground, earth”) + -ilis → humilis (“lowly, humble”)
- pār, par- (“even, equal”) + -ilis → parilis (“equal, like”)
- herba (“grass”) + -ilis → herbilis (“fed on grass”)
Third-declension two-termination adjective.
Originally from the above -ilis added to i stems, later used freely.
-īlis (neuter -īle); third-declension two-termination suffix
- -ile; used to form an adjective, usually from a noun, indicating a relationship or a pertaining to.
- aedis (“building”) + -ilis → aedīlis (“of buildings”) (attested as substantive)
- hostis (“enemy”) + -ilis → hostīlis (“of the enemy, unfriendly, hostile”)
- puer (“boy”) + -ilis → puerīlis (“of boys, boyish, immature”)
- erus (“master”) + -ilis → erīlis (“of the master”)
Third-declension two-termination adjective.