perceptive,"['acute', 'apperceptive', 'apprehensive', 'discerning', 'discriminating', 'incisive', 'insightful', 'keen', 'knifelike', 'observant', 'observing', 'penetrating', 'penetrative', 'piercing', 'quicksighted', 'sharp', 'sharpeyed', 'sharpsighted', 'subtle', 'understanding']"