Hearty nonsense about transport (6)
I believe the answer is:
robust
'hearty' is the definition.
(I've seen this in another clue)
'nonsense about transport' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'about' is an insertion indicator.
'transport' becomes 'bus' (busing is a kind of transporting).
'rot' placed around 'bus' is 'ROBUST'.
(Other definitions for robust that I've seen before include "No-nonsense" , "Having a strong constitution" , "Strong and vigorous" , "Athletic" , "Turbos (anag) - fit for purpose!" .)