Prurient look (4)
I believe the answer is:
leer
'prurient look' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for leer that I've seen before include "Suggestive or sneering look" , "Lascivious gaze" , "Ogle, smirk" , "Lecherous look" , "Suggestive or sneering grin" .)