Pale 1950s youth sought by police? (6)
I believe the answer is:
wanted
'sought by police?' is the definition.
(wanted by police)
'pale 1950s youth' is the wordplay.
'pale' becomes 'wan' (wan can mean pale or grey).
'1950s youth' becomes 'ted' (member of a 1950s subculture).
'wan'+'ted'='WANTED'
(Other definitions for wanted that I've seen before include "Lacked; type of police poster" , "Wished-for" , "sought by police?" , "Desired, needed" , "Desired or wished for" .)