Synonyms for Perceptive (same or very similar meaning)
WordNet sense 1 (quick to notice; showing quick and keen perception):
observant
WordNet sense 2 (exhibiting insight or clear and deep perception):
insightful
WordNet sense 3 (quick to understand):
apprehensive, discerning
WordNet sense 4 (having or demonstrating ability to recognize or draw fine distinctions):
acute, incisive, keen, penetrating, sharp
From the ODE community, based on WordNet
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