Knack

1. Something performed, or to be done, requiring aptness and dexterity; a trick; a device.
2. To speak affectedly.
3. A readiness in performance; aptness at doing something; skill; facility; dexterity.
4. A petty contrivance; a toy; a plaything; a knickknack.
5. To crack; to make a sharp, abrupt noise to chink.