Someone who is excessively keen or eager, possibly making others look bad; a brown-noser.(noun)
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Use "keener" in a sentence
"He was an adorable boy, his expression keener and more changeable than that of the changeling."
"It would be difficult to explain what the change was, but it forcibly struck Alain: the air was more dignified, the expression keener; there was a look of conscious power and command about the man even at that distance; the intense, concentrated intelligence of his eye, his firm lip, his marked features, his projecting, massive brow, would have impressed a very ordinary observer."
"The more absolutely he fails, the higher, it is probable, he will reckon his own merits; and the keener will be the sense of injury in that he whose work is of so high a nature cannot get bread, while they whose tasks are mean are lapped in luxury."