call it quits

/K AO1 L IH0 T K W IH0 T S/
verb
  1. 1

    To conclude; to quit or stop an activity, especially after applying oneself to it for a significant period of time.

  2. 2

    To declare debts resolved to one another

Source: https://en.wiktionary.org/wiki/call%20it%20quits