Possible reason for booking manual worker before party (8)
I believe the answer is:
handball
'possible reason for booking manual' is the definition.
I can't judge whether this defines the answer.
'worker before party' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker).
'before' means one lot of letters go next to another.
'party' becomes 'ball' (ball is a kind of party).
'hand'+'ball'='HANDBALL'
Can you help me to learn more?
(Other definitions for handball that I've seen before include "Offence from soccer" , "kind of foul" , "Game played in a walled court" .)