In contrast to the huge category that we have just met, there is a rather small number of Latin adjectives formed by adding the suffix -īlisto the noun base. These regularly appear in English as words ending in –ile, occasionally in –il. Most conspicuous, perhaps, are the adjectives relating to the periods of human life (especially, a man’s life). The Latin word for a baby was infans, infant-is; “like a baby” was infant-ilis, whence English infantile. Because “boy” was puer (a 2nd declension subtype), “boyish” was puer-ilis (E puerile). From juvenis (“young man”) came juven-ilis (E juvenile). The noun vir (“man”) produced the adjective vir-ilis (E virile), and senex, sen-is (“old man”) yielded sen-ilis (E. senile). There was also a Latin adjective to describe an old woman—anilis, from the noun ănus (pronounced differently in Latin from ānus [E anus], a word that the Romans considered crude). There does exist an English word anile (“like an old woman”), but its rareness is probably the result of its similarity to anal (< analis, < ānus).
Outside of this coherent little group, there are only a few important –ilis derivatives of this type in English: servile (“like a slave”) < servilis < servus; hostile (“like an enemy”) < hostilis < hostis; civil (“pertaining to a citizen”) < civilis < civis; and gentile (“pertaining to the nations”) < gentilis < gens, gent-is (“clan,” “race”). The last, of course, has had its English meaning specialized to “non-Jewish,” from the Biblical contrast between the Jews and the gentiles. Gentile has three rather curious DOUBLETS—gentle, genteel, and jaunty, all transmitted and influenced by French gentil.