What it means
To lark about is to mess around in a daft, playful way instead of doing what you’re meant to. Think giggling, making a racket, winding your mates up, generally being a nuisance but not in a nasty way. Often said to kids, but adults do it too when work’s quiet and no one important is watching. Basically harmless chaos with plenty of cheek.
Usage examples
"Oi, stop larking about and do the washing up, you’ve turned the tea towel into a cape and you’re knighting the cat with a spatula."
"The lads were larking about with the hose in the garden and soaked the washing their nan had just hung out."
"Less larking about at the back, you two, the bus driver can see everything in that mirror."
"They were meant to be stacking chairs, but instead they were larking about with the microphone and doing fake announcements."
"Quit larking about in the shop, will you, before you knock that display over and get us all moaned at."
Where it comes from
It comes from lark, a long-standing British English noun for a bit of carefree fun or a daft escapade, recorded from the early 1800s. From there, lark about grew naturally into the verb phrase for messing around, clowning about, and carrying on in a cheeky, harmless way.
