The adjective is borrowed from Late Latin ovīnus (“ovine”) + English -ine (suffix with the sense ‘of or relating to’ forming adjectives). Ovīnus is derived from Latin ovis (“sheep”) (ultimately from Proto-Indo-European *h₂ówis (“sheep”), possibly from *h₂ew- (“to clothe oneself, dress; to be dressed”) in the sense of something that provides woollen clothing) + -īnus (suffix with the sense ‘of or relating to’ forming adjectives).
The noun is derived from the adjective.