Conspiring group in taxi with Capone? (5)
I believe the answer is:
cabal
'conspiring group' is the definition.
(I've seen this in another clue)
'taxi with capone?' is the wordplay.
'taxi' becomes 'cab' (synonyms).
'with' says to put letters next to each other.
'capone?' becomes 'Al' (gangster Al Capone).
'cab'+'al'='CABAL'
'in' is the link.
(Other definitions for cabal that I've seen before include "Group of conspirators" , "Intriguing group" , "Camp" , "Secret political group" , "Clique of plotters" .)