Leer at (4)
I believe the answer is:
ogle
'leer at' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ogle that I've seen before include "flirtatious look" , "Stare at in a lecherous manner" , "Gawp" , "Perv" , "Eye flirtatiously" .)