Learn how to say Knack correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word knack:
[usually in singular]
an acquired or natural skill at doing something:
he had a knack for communicating
a tendency to do something:
John had the enviable knack of falling asleep anywhere
late Middle English (originally denoting a clever or deceitful trick): probably related to obsolete knack ‘sharp blow or sound’, of imitative origin (compare with Dutch knak ‘crack, snap’)
Remember that knack is spelled with a k at the beginning, although it is not heard when you say the word. Other words that begin with kn- include knapsack, knead, knee, knickers, knit, knock, knot, know, and knuckle.