Scheming bunch in taxi with Capone? (5)
I believe the answer is:
cabal
'scheming bunch' is the definition.
(a cabal is a secretive group of people)
'taxi with capone?' is the wordplay.
'taxi' becomes 'cab' (synonyms).
'with' means one lot of letters go next to another.
'capone?' becomes 'al'.
'cab'+'al'='CABAL'
'in' acts as a link.
(Other definitions for cabal that I've seen before include "Camp" , "Small party" , "Intrigue, clique" , "Intriguing group" , "secret council" .)