Has no use for grain-carrying ship (6)
I believe the answer is:
scorns
'has no use for' is the definition.
(I've seen this in another clue)
'grain-carrying ship' is the wordplay.
'grain' becomes 'corn' (corn is a kind of grain).
'carrying' means one lot of letters goes inside another.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'corn' put into 'ss' is 'SCORNS'.
(Other definitions for scorns that I've seen before include "Derides or desises" , "Holds in contempt" , "Has or shows contempt for" , "Despises, has contempt for" , "Has contempt for, disdains" .)