Jokers (4)
I believe the answer is:
'jokers' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for wags that I've seen before include "Habitual jokers" , "group with team players, esp when travelling" , "Moves briskly to and fro with swag (4)" , "Moves to and fro like dog's tail" .)