someone's heart out

English

(reflexive, idiomatic) With great effort or enthusiasm.
Synonym: (vulgar) someone's arse off
- 2016 November 13, Josh Gross, “Conor McGregor KOs Eddie Alvarez to become UFC's first two-class champion”, in The Guardian‎^[1]:
  “I thought that I did enough to finish out that last round and get the draw,” Thompson said. “Of course, I’d rather have the win but it is what it is. We both went out there and fought our hearts out. I hope we can do it again. Nothing else would interest me. I want the rematch. I don’t want anything but that rematch.”