Cicely madly pursues black vehicle (7)
I believe the answer is:
bicycle
'vehicle' is the definition.
(bicycle is a kind of vehicle)
'cicely madly pursues black' is the wordplay.
'madly' indicates anagramming the letters.
'pursues' is a charade indicator (letters next to each other).
'black' becomes 'b' (as in pencil classifications).
'cicely' is an anagram of 'icycle'.
'icycle' after 'b' is 'BICYCLE'.
(Other definitions for bicycle that I've seen before include "Eg, penny-farthing" , "Form of transport" , "Two-wheeled transport" , "Bike" , "M an-powered vehicle" .)