Impassive detectives binding crowd over (6)
I believe the answer is:
stolid
'impassive' is the definition.
(thesaurus)
'detectives binding crowd over' is the wordplay.
'detectives' becomes 'dis' (Detective Inspectors, DIs).
'binding' is an insertion indicator.
'crowd' becomes 'lot' (I've seen this in other clues**).
'over' says the letters should be written in reverse.
'dis' placed around 'lot' is 'dilots'.
'dilots' in reverse letter order is 'STOLID'.
(Other definitions for stolid that I've seen before include "Impassive, unemotional" , "Not excitable or emotional" , "Not excitable, doesn't show emotion" , "Impassive or apathetic" , "Not excitable, unemotional" .)