Superlative form of brainy: most brainy.(adjective)
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Use "brainiest" in a sentence
"Quote: “He was known as the brainiest boxman in the history of latter-day baseball.”"
"Each sister married twice, acquiring names along the way that bespeak American royalty: Babe Mortimer Paley; her competitive middle sister, Betsey Roosevelt Whitney; and the so-called brainiest, Minnie Astor Fosburgh."
"One of America's "brainiest" politicians, Frank is a household name in his district, and he has $1 million - much more than Bielat has - to spend in the final month before the midterm vote."