LATIN DICTIONARYLexicon Latīnum
suffixfirst/second-declension suffix

-cus

-cus (feminine -ca, neuter -cum)
Classical[kʊs]Ecclesiastical[kus]

Meaning

  1. morphemesuffixsuffixed to nouns, forms adjectives
    iuvenis + -cus → iuvencus
    Mārs + -cus → Mār(t)cus

Origins

From Proto-Italic *-kos, from Proto-Indo-European *-kos. Cognate with Ancient Greek -κός (-kós), Proto-Germanic *-gaz, Sanskrit -शस (-śasa) and Proto-Slavic *-kъ. PIE *-ko- on noun stems carried the meaning 'characteristic of, like, typical, pertaining to', and on adjectival stems it acted emphatically.

Quick answers

What does -cus mean in Latin?
-cus, a suffix, means “suffixed to nouns, forms adjectives”.
How do you pronounce -cus?
In classical Latin, [kʊs]; in ecclesiastical (church) Latin, [kus].