finally (adv.)

early 14c., from Old French final "final, last," and directly from Late Latin finalis "of or pertaining to an end, concluding, final," from finis "end" (see finish (v.)). As a noun, late 14c., "that which comes last;" meaning "final contest" in a sporting sense is from 1880. As a shortening of final examination, from 1880.

common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).

Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.