Clean media boss’s vehicle (5)
I believe the answer is:
moped
'vehicle' is the definition.
(moped is a kind of vehicle)
'clean media boss's' is the wordplay.
'clean' becomes 'mop' (mopping is a kind of cleaning).
'media boss' becomes 'ed' (short for editor).
'mop'+'ed'='MOPED'
(Other definitions for moped that I've seen before include "Light motorbike" , "means of transport" , "Mooned around" , "Vehicle - was blue" , "Motor vehicle - languished" .)