Reveal, to a poet (3)
I believe the answer is:
ope
'reveal to a poet' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ope that I've seen before include "Undo, unfold (poetic)" , "Literary form of open" , "Unlock, undo (poetic)" , "moon about, missing maiden" .)