Crooked, extremely slick partners above suspicion (4-5)
I believe the answer is:
skew-whiff
'crooked' is the definition.
(both can mean wonky)
'extremely slick partners above suspicion' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'partners' becomes 'ew' (East and West are partners in the game bridge).
'above' is a charade indicator (letters next to each other).
'suspicion' becomes 'whiff' (as in a whiff of suspicion).
'slick' with its middle taken out is 'sk'.
'sk'+'ew'+'whiff'='SKEW-WHIFF'
(Other definitions for skew-whiff that I've seen before include "Crooked - out of alignment" , "Cockeyed" , "Awry" , "Not straight" .)