look up any word, like the eiffel tower:
 
1.
When you do something that violates the Man Code.
John: How come Phil is not coming to the bachelor party?

Roger: Sarah wanted him to stay in and watch Sex and the City 2.

John: Yeah, that's a definite man foul.
by SafeHouse July 04, 2010
 
2.
non man-like behavior
Eating Texas fries with a fork is a manfoul.
by rj2 July 02, 2010