Trick WC Fields initially rejected (4)
I believe the answer is:
fool
'trick' is the definition.
(I've seen this in another clue)
'wc fields initially rejected' is the wordplay.
'wc' becomes 'loo' (both can mean a toilet).
'initially' suggests taking the first letters.
'rejected' is a reversal indicator.
The first letter of 'fields' is 'f'.
'loo'+'f'='loof'
'loof' in reverse letter order is 'FOOL'.
(Other definitions for fool that I've seen before include "Idiot" , "Dessert of pureed fruit and cream" , "One and his money are soon parted" , "mug" , "Jester; dupe" .)