The definition of a knack is a clever skill or special talent for doing something quickly.(noun)
An example of knack is the ability to cook something delicious for unexpected dinner guests.
See knack in Webster's New World College Dictionary
Origin: ME knak, sharp blow: see knock
See knack in American Heritage Dictionary 4
Origin: Middle English knakke
Origin: , from Middle Dutch cnacken, to strike, crack
Origin: , probably of imitative origin.
Learn more about knack