dirt-stach

When your face gets dirty and there's a shadow of dirt on your upper lip giving the appearance of a mustache made of dirt:

Obviously Joey hasn't washed his face in days; he's rocking the 'dirt-stache'!

by RedBombshell February 24, 2015

Bu stache

When a cat has a built in mustache.

This cat is a bu because they have a fine bu stache.

by Weinerdog17 April 12, 2021