i Register
In some senses, knack is marked as obsolete, UK. Watch for register when choosing this word.
ADJ
happy | uncanny
unhappy
She has an unhappy knack for saying the wrong thing at important moments.
VERB + KNACK
have
acquire, develop, get
She developed a real knack for remembering people's names at parties.
lose
After years away from playing guitar, she worried she had lost the knack for it.
PREP
~ for
She has a real knack for making people feel comfortable at parties.
~ of
She has a real knack of making people feel comfortable at parties.
~ to
She discovered there was a real knack to decorating cakes neatly.