knock
n. countablen. the sound of someone hitting a door with their hand to get your attention. It can also mean a sharp hit or a piece of criticism that hurts your confidence.
n. a sharp blow or the sound produced by a hard object striking a surface. In informal contexts, it refers to a critical remark or a setback that damages one's reputation or morale.
I heard a loud knock at the front door.
Losing the first match was a real knock to the team's confidence.
Despite the knock he took to his professional reputation during the scandal, he managed to rebuild his career through persistent community service and transparency.
From Middle English knokken, from Old English cnocian, ġecnocian, ġecnucian, cnucian (“to knock, pound on, beat”), from Proto-West Germanic knokōn, from Proto-Germanic knukōną (“to knock”), a suffixed form of knu-, knew- (“to pound on, beat”), from Proto-Indo-European gnew-, gen- (“to squeeze, pinch, kink, ball up, concentrate”). The English word is cognate with Middle High German knochen (“to hit”), Old English cnuian, cnuwian (“to pound, knock”), Old Norse knoka (compare Danish knuge (“to squeeze”), Swedish knocka (“to hug”)).
Often used in the phrase 'a knock to' when describing a blow to abstract concepts like pride or confidence.