Played detective about to flip (5)
I believe the answer is:
acted
'played' is the definition.
('act' can be a synonym of 'play')
'detective about to flip' is the wordplay.
'detective' becomes 'det' (abbreviation for detective).
'about' becomes 'ca' (abbreviation for 'circa').
'to flip' says the letters should be written backwards.
'det'+'ca'='detca'
'detca' back-to-front is 'ACTED'.
(Other definitions for acted that I've seen before include "Behaved like thespian" , "Behaved or performed" , "Play a role" , "Posed as" , "appeared on stage" .)