Son who plays truant (2-4)
I believe the answer is:
no-show
'truant' is the definition.
(I know that truant can be written as no-show)
'son who plays' is the wordplay.
'plays' indicates an anagram.
'son'+'who'='sonwho'
'sonwho' anagrammed gives 'NO-SHOW'.
(Other definitions for no-show that I've seen before include "One failing to appear as booked" , "Absentee" , "One who fails to arrive" , "Person who fails to cancel -- who's on (anag)" , "Individual neither using nor cancelling a ticket" .)