knack

Short definition from Wiktionary

Noun

1. 1
   A readiness in performance; aptness at doing something.
2. 2
   A petty contrivance; a toy.
3. 3
   Something performed, or to be done, requiring aptness and dexterity.

Verb

1. 1
   To crack; to make a sharp, abrupt noise; to chink.
2. 2
   To speak affectedly.

Proper noun

1. 1
   A surname.