: to hit something (such as a door) with the knuckles of your hand or with a hard object (such as a knocker) in order to get people's attention
: to hit (something or someone) in a forceful way
: to touch or hit someone or something in a way that is not planned or intended
: a hard, sharp hit
: the sound made by a hard hit
: an experience that makes you less confident or successful for a period of time : a difficult or painful experience
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