finish off

/F IH1 N IH0 SH AO1 F/
verb
  1. 1

    To finish completely.

    โ€œI was hungry, so I finished off the last of the cakes.โ€

  2. 2

    To kill.

    โ€œIt was the blow to the head that finished him off, not the bullet wound.โ€

Source: https://en.wiktionary.org/wiki/finish%20off