Clever flipping vehicles (5)
I believe the answer is:
trams
'vehicles' is the definition.
(tram is a kind of vehicle)
'clever flipping' is the wordplay.
'clever' becomes 'smart' (similar in meaning).
'flipping' is a reversal indicator.
'smart' reversed gives 'TRAMS'.
(Other definitions for trams that I've seen before include "old vehicles" , "public transport" , "People movers" , "Not seen in London" , "silk yarns" .)