Trash shirt

Basically any shirt a man owns that he wouldn't go on a date in. A t-shirt used for sleeping, going to the liquor store, or hanging around the house in.

"Hey that Laker game is on right now, wanna head to the pub"?

"Nah, my lady has me doing house chores, and I'm still in my trash shirt form yesterday".

And/or

"the doorbell. Hand me that trash shirt.