Taking the piss

British Slang

Definition

Mocking or ridiculing someone, or acting cheekily by taking liberties/being blatantly unreasonable.

Examples

"He spent the whole meeting taking the piss out of the new guy’s haircut."

"Are you taking the piss, expecting me to cover your shift with no notice?"

"Charging fifteen quid for a basic toastie is taking the piss."