intestinal fortitude

noun

1. courage; resoluteness; endurance; guts:

   to have intestinal fortitude.

Word History and Origins

Origin of intestinal fortitude¹

First recorded in 1940–45

Example Sentences

The president felt he was showing intestinal fortitude by resisting pressure to maintain a residual force, which he insists would have led to an escalation of the conflict.

From Washington Post

This shortage of intestinal fortitude had enormous military consequences.

From The Daily Beast