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. © 2015 Farlex, Inc, all rights reserved.

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. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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