(UK) To fail to attend school or work without permission; to play truant (usually as in 'to bunk off').
Origin of bunk
Sense of sleeping berth possibly from Scottish English bunker (“seat, bench”), origin is uncertain but possibly Scandinavian. Confer Old Swedish bunke (“boards used to protect the cargo of a ship”). See also boarding, flooring and confer bunch.
If I tell you we'll be bunk mates.
Donnie can bunk in our office.
They've got a bunk in the back room of the restaurant where he washes dishes.
She returned to her bunk and lay down, cold fear filling her.
She sat on her bunk while Lankha climbed atop his.