Chopsy
British SlangDefinition
Mouthy or lippy; prone to cheeky, impudent backchat or boastful talk.
Examples
"Don’t get chopsy with the teacher, or you’ll land yourself in detention."
"He got a bit chopsy after a few pints and started mouthing off at the bouncers."
"She’s proper chopsy on the group chat but quiet as a mouse in person."