A grand prophet goes west to get suits (6)
I believe the answer is:
agrees
'suits' is the definition.
(agreeing is a kind of suiting)
'a grand prophet goes west' is the wordplay.
'a grand' becomes 'ag' (I've seen this in other clues).
'prophet' becomes 'seer' (I've seen this before).
'goes west' says the letters should be written backwards.
'seer' written backwards gives 'rees'.
'ag'+'rees'='AGREES'
'to get' acts as a link.
(Other definitions for agrees that I've seen before include "Assents, concurs" , "Shakes hands" , "Grease (anag.)" , "Accedes or concurs" , "is in accord" .)