1. verb To speak negatively or unflatteringly about someone or something. Why are you always dirty-mouthing Tiffany? You don't even know her that well!
2. noun A person who uses obscenities, vulgarities, or profanities in their speech, especially at inappropriate times. Hey, you dirty-mouth! If I hear you speaking like that around your grandmother again, you're going to be grounded for a week! Well there's no need to be a dirty-mouth about it, Rick. You could have just said no like a civilized person.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
1. n. a person who talks dirty. (see also bad-mouth.) Some dirty-mouth yelled out the most obscene things during the meeting.
2. tv. to speak ill of someone or something. (see also bad-mouth.) Please stop dirty-mouthing my friends.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.