Sharp detectives can concoct case (8)
I believe the answer is:
distinct
'sharp' is the definition.
('distinct' can be similar in meaning to 'sharp')
'detectives can concoct case' is the wordplay.
'detectives' becomes 'dis' (Detective Inspectors, DIs).
'can' becomes 'tin' ('tin' can be a synonym of 'can').
'case' says to hollow out the word (remove centre letters).
'concoct' with its centre taken out is 'ct'.
'dis'+'tin'+'ct'='DISTINCT'
(Other definitions for distinct that I've seen before include "Definite and unmistakeable" , "Recognisably different" , "easily recognisable" , "Readily distinguishable" , "Clear and separate from others" .)