Late 15th century; earliest use found in John Skelton (c1460–1529), poet. From Middle French repentin sudden, unexpected or its etymon classical Latin repentīnus sudden from repent-, repēns sudden, of uncertain origin + -īnus.
Definition of repentine in US English:
repentine
adjectiverɪˈpɛntʌɪn
rare
Sudden.
Origin
Late 15th century; earliest use found in John Skelton (c1460–1529), poet. From Middle French repentin sudden, unexpected or its etymon classical Latin repentīnus sudden from repent-, repēns sudden, of uncertain origin + -īnus.