Anguish from Detective Sergeant imprisoning European couple (7)
I believe the answer is:
despair
'anguish' is the definition.
(thesaurus)
'detective sergeant imprisoning european couple' is the wordplay.
'detective sergeant' becomes 'DS' (abbreviation for detective sergeant).
'imprisoning' is an insertion indicator.
'european' becomes 'E' (abbreviation e.g. EU).
'couple' becomes 'pair' (synonyms).
'ds' enclosing 'e' is 'des'.
'des'+'pair'='DESPAIR'
'from' acts as a link.
(Other definitions for despair that I've seen before include "The feeling that nothing will turn out well" , "Feeling of hopelessness" , "displaying lack of optimism" , "gloom" , "Resignation" .)