Sharp detectives returned fool to court (8)
I believe the answer is:
distinct
'sharp' is the definition.
('distinct' can be similar in meaning to 'sharp')
'detectives returned fool to court' is the wordplay.
'detectives' becomes 'dis' (Detective Inspectors, DIs).
'returned' shows that the letters should be reversed in order.
'fool' becomes 'nit' (I've seen this before).
'to court' becomes 'ct'.
'nit' backwards is 'tin'.
'dis'+'tin'+'ct'='DISTINCT'
(Other definitions for distinct that I've seen before include "Definite or different in kind" , "Easy to perceive" , "Plain" , "Clear and separate from others" , "Discrete, clear-cut" .)