I. adverb
: permanently
II. adverb
1.
a. : with the provision that one keep what he has won
the two men were playing the game for keeps
b. : with deadly seriousness : with the firm intention of winning or overcoming if at all possible
found out that his rival was not fooling but competing with him for keeps
2. : with the intention of remaining in a particular state or relationship for good : permanently
after his experience in foreign countries he came home for keeps
3. : with finality : with the result of ending the matter
stole their crown jewels … and for keeps — Ethel M. Thornbury
plugged for keeps in a gun duel with a desperado — John McCarten