Antonyms for Dull (opposite meaning)
WordNet sense 1 (make sharp or sharper):
sharpen
WordNet sense 2 (full of life and energy):
lively
WordNet sense 3 (keenly and painfully felt; as if caused by a sharp edge or point):
sharp
WordNet sense 4 (emitting or reflecting light readily or in large amounts):
bright
From the ODE community, based on WordNet
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