harden one's heart

harden (one's) heart

To stop or cause one to stop feeling kindness and compassion. I worry that all the trauma she's already been through at such a young age will harden her heart.
See also: harden, heart
Farlex Dictionary of Idioms.

harden one's heart

Feel no sympathy for, as in We can't afford to give them more; we'll just have to harden our hearts when they ask . [Late 1300s]
See also: harden, heart
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • harden
  • harden (one's) heart
  • harden your heart
  • get off (one's) high horse
  • get off high horse
  • wipe the/that grin off (one's) face
  • wipe the/that smile, grin, etc. off your/somebody's face
  • All right already!
  • all right(y) already
  • righty