knife
an atmosphere that you could cut with a knife: seeatmosphere.
before you can say knife very quickly; almost instantaneously. informal, dated
get (or stick) the knife into (or in) someone do something hostile or aggressive to someone. informal
go (or be) under the knife have surgery. informal
like a (hot) knife through butter very easily; without any resistance or difficulty.
night of the long knives: seenight.
twist (or turn) the knife deliberately make someone's grief or problems worse.
1991Mavis NicholsonMartha Jane & Me While she and I were playing the cat-and-mouse game of these stories, I would sometimes, just to twist the knife a little further, ask about the little girl's father.
the knives are out (for someone) there is open hostility (towards someone). informal