Casual worker absent earlier (7)
I believe the answer is:
offhand
'casual' is the definition.
('offhand' can be a synonym of 'casual')
'worker absent earlier' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker**).
'absent' becomes 'off' (I've seen this in other clues).
'earlier' means one lot of letters go next to another.
'hand' put after 'off' is 'OFFHAND'.
(Other definitions for offhand that I've seen before include "Ungraciously curt" , "with a careless manner" , "Casual or curt, like discarded glove?" , "Brusque" , "Casually rude" .)