How Well Do You Know English Slang?
Old English rarian "roar, wail, lament, bellow, cry," probably of imitative origin (cf. Middle Dutch reeren, German röhren "to roar;" Sanskrit ragati "barks;" Lithuanian reju "to scold;" Old Church Slavonic revo "I roar;" Latin raucus "hoarse"). Related: Roared; roaring.
late 14c., from roar (v.) and Old English gerar.