Dismiss society hack wasting hours (4)
I believe the answer is:
sack
'dismiss' is the definition.
(I know that dismiss can be written as sack)
'society hack wasting hours' is the wordplay.
'society' becomes 's' (common abbreviation in names of organisations).
'wasting' indicates named letters should be taken away.
'hours' becomes 'h'.
'hack' with 'h' taken out is 'ack'.
's'+'ack'='SACK'
(Other definitions for sack that I've seen before include "A bag for Falstaff's drink" , "Flour or grain bag" , "Plundering by a mob" , "Discharge" , "Fire - rifle" .)