Making out to be perceptive (10)
I believe the answer is:
discerning
I believe this is a double definition.
'making out' is the first definition.
('discern' can be a synonym of 'make out')
'be perceptive' is the second definition.
('discerning' can be similar in meaning to 'perceptive')
'to' acts as a link.
(Other definitions for discerning that I've seen before include "clever" , "Making out" , "showing good taste" , "Particular" , "Unobtrusively perceptive" .)