Synonyms for Perceptive:

adj.

alert, sensitive (adjective)
discreet, intuitive, incisive, discerning, responsive, sagacious, penetrative, observant, keen, conscious, aware, astute, perspicacious, penetrating, rational, wise, insightful, sharp, acute, judicious.
aware (adjective)
aware, sensory, responsive, cognizant, mindful, familiar with, sentient, attentive, alert, feeling, appreciative, observant, Apprised, astute, conscious, sensitive.
clairvoyant (adjective)
insightful, intuitive, sagacious, clear-sighted, foresighted, prophetic, prescient, second-sighted, prognostic, farsighted, forseeing, discerning, clairvoyant, provident.
discriminating (adjective)
discerning.
eagle-eyed (adjective)
sharp-eyed.
impressionable (adjective)
sensitive.
intelligent (adjective)
penetrating.
sensitive (adjective)
sensory.
visionary (adjective)
foresighted.

n.

clear-sighted, academic, intelligent, brilliant, wise, able, smart, bright. biting, CODED, acid, cheap, cutting, bland, astringent, acrid, backhanded, allusive. probing, careful, trenchant. discerning (noun)
judicious, perspicacious, rational, discreet.
perceptive (noun)
incisive, knifelike, insightful, discriminating, sharp-eyed, sharp-sighted, piercing, penetrating, observing, discerning, apprehensive, apperceptive, quick-sighted, penetrative, sharp, understanding, keen, subtle, acute, observant.

Other synonyms:

intelligent, probing. trenchant. smart. judicious
wise.
observant
perspicacious.
well-advised
judicious.
Other relevant words:
penetrating, probing, apprehensive, piercing, able, knifelike, brilliant, penetrative, sharp, perspicacious, apperceptive, careful, rational, quick-sighted, clear-sighted, judicious, bright, smart, trenchant, discriminating, acute, understanding, incisive, intelligent, alert, sharp-eyed, subtle, discreet, sharp-sighted, keen, observing, wise.