Crystal gazer (4)
I believe the answer is:
seer
'crystal gazer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for seer that I've seen before include "One divines the future" , "Distinguishing quality" , "Sage with 20ac" , "Fortune-teller" , "Prophet or clairvoyant" .)