～(て) しまう
～(て) しまう · ～(te) shimau · JLPT N4 · noun
to end up ~
しまう = to put away, finish off: the deed is done, no undo
しまう on its own means to put away or close up. Attached to a て-form verb, it marks the action as fully finished, often by accident or with regret: 食べてしまう = to end up eating it all. Casual speech shrinks it to ちゃう.