look up any word, like trill:
 
1.
A politicaly correct term for guts
Though Mohamad Ali may seem to have intestinal fortitude he is not healthy.
by Light Joker March 19, 2004
 
2.
Mental Toughness
Navy SEALs possess intestinal fortitude. Frequently heard during Hell Week.
by DeepSix66 October 15, 2013