Look out! Watch where you're going! Be more careful! Hey, watch it! You nearly knocked my drink over. Watch it, pal, you're in my way!
1. Inf. Be careful. Rachel: Watch it! There's a broken stair there. Jane: Gee, thanks. Mary: Watch it! There's a pothole in the street. Bob: Thanks.
2. Inf. Do not act or talk that way. Sally: I really hate John! Sue: Watch it! He's my brother! Bill: You girls always seem to take so long to do a simple thing like getting dressed. Mary: Watch it!
exclam. Be careful!; Watch your step!; Careful of what you say! You’re walking on thin ice. Watch it!