(especially with reference to an animal's tail) move or cause to move rapidly to and fro

his tail began to wag

the dog went out, wagging its tail

a single rapid movement from side to side

a chirpy wag of the head

play truant from (school)

he began hanging out with bad people and wagging school

a person who makes jokes; a joker

one wag shouted, ‘On that count you've got about three supporters!’

a person who plays truant

Boogie plays the wag from school

a wife or girlfriend of a sports player, typically characterized as having a high media profile and a glamorous lifestyle

the image was taken at the former WAG's new rural home

the mother-of-two beamed alongside fellow WAGs as they dutifully cheered on their men