City folk retired detective deplored (8)
I believe the answer is:
lamented
'deplored' is the definition.
('lament' can be a synonym of 'deplore')
'city folk retired detective' is the wordplay.
'city' becomes 'LA' (Los Angeles).
'folk' becomes 'men' (both can mean people).
'retired' says the letters should be written backwards.
'detective' becomes 'det' (abbreviation for detective).
'det' reversed gives 'ted'.
'la'+'men'+'ted'='LAMENTED'
(Other definitions for lamented that I've seen before include "Expressed disappointment about (something)" , "Mourned (a death)" , "Non compos mentis" , "Mourned or grieved for" , "Bemoaned" .)