What it means
To mug someone off is to make a proper fool of them, whether by chatting bare lies, ditching a plan last minute, or taking them for an absolute melt. It's that moment you treat a mate like they're clueless and you're slick, leaving them standing there while everyone clocks what you done. Proper disrespectful, innit.
Usage examples
"He proper mugged me off, said he'd sort the tickets and then ghosted the group chat."
"Don't let her mug you off like that, you ain't no side piece, mate."
"They were mugging him off in front of everyone and he just stood there smiling like he didn't get it."
