Conspiring group in taxi with a learner driver (5)
I believe the answer is:
cabal
'conspiring group' is the definition.
(I've seen this before)
'taxi with a learner driver' is the wordplay.
'taxi' becomes 'cab' (synonyms).
'with' is a charade indicator (letters next to each other).
'learner driver' becomes 'l' (learner drivers have L-plates on their cars).
'cab'+'a'+'l'='CABAL'
'in' is the link.
(Other definitions for cabal that I've seen before include "Secret political group" , "Plotting group" , "Intrigue, clique" , "Secret plot or the people engaged in it" , "Small group of (eg political) plotters" .)