Reveal fish beneath punt (6)
I believe the answer is:
betray
'reveal' is the definition.
(betraying is a kind of revealing)
'fish beneath punt' is the wordplay.
'fish' becomes 'ray' (ray is a kind of fish**).
'beneath' is a charade indicator (letters next to each other) (in a down clue).
'punt' becomes 'bet' (I've seen this in other clues).
'ray' after 'bet' is 'BETRAY'.
(Other definitions for betray that I've seen before include "Be disloyal; reveal" , "Inform on (someone)" , "Inadvertently reveal" , "Break confidence" , "Be disloyal to, abuse trust" .)