Derides vegetable in boat (6)
I believe the answer is:
scorns
'derides' is the definition.
(I've seen this in another clue)
'vegetable in boat' is the wordplay.
'vegetable' becomes 'corn' (I am not sure about this - if you are sure you should believe this answer much more).
'in' means one lot of letters goes inside another.
'boat' becomes 'SS' (prefix in ship names eg SS Great Britain).
'corn' going within 'ss' is 'SCORNS'.
Can you help me to learn more?
(Other definitions for scorns that I've seen before include "Disdains and spurns" , "Has contempt for, disdains" , "Holds in contempt" , "Looks down on" , "Despises, has contempt for" .)