A smug or mischievous grin usually used after someone says or does something mischievous or sarcastic.
I knew he had done something just because of that shitty grin on his face
by brownbob August 31, 2010
1 more definition
an overly large, or irritatingly smug smile, showing an excessive pride in oneself or one's achievements
her husband was wearing a shitty grin, thinking he had won
by DTinLA April 20, 2011