WordWeb Online

1. Of or relating to perception
   "perceptive faculties"
    
2. Having the ability to perceive or understand; keen in discernment
   "a perceptive eye"; "a perceptive observation"

See also: acute, apperceptive, apprehensive, discerning, discriminating, incisive, insightful, keen, knifelike, observant, observing, penetrating, penetrative, perceive, perception, perceptively, perceptiveness, piercing, quick-sighted, sharp, sharp-eyed, sharp-sighted, subtle, understanding

Antonym: unperceptive