1. rude slang Something stupid or trivial. I won't argue with you about this dumb shit for a second longer!

2. rude slang A stupid person. Listen, you dumb shit, I'm in charge here, so you better do what I say! Oh right, like I would listen to him—he's a dumb shit!

3. rude slang Describing someone or something as stupid. In this usage, the term is often hyphenated or spelled as one word. I won't argue with you about this dumbshit idea for a second longer!