The grotty sludge that hardens to a putrid film on the botttom of a coffee mug when left on your desk for a few days, or weeks.
Look at the filthy mug muck that's formed on that lazy bastard's coffee mug!
by JJBrubaker April 15, 2007

5 Words Related to mug muck

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×