Priest with proclamation to foretell (7)
I believe the answer is:
predict
'to foretell' is the definition.
(synonyms)
'priest with proclamation' is the wordplay.
'priest' becomes 'pr'.
'with' is a charade indicator (letters next to each other).
'proclamation' becomes 'edict' (I've seen this in another clue).
'pr'+'edict'='PREDICT'
(Other definitions for predict that I've seen before include "Estimate consequence of" , "Prophesy - portend" , "Foretell, prophesy" , "act as oracle" , "Foresee" .)