you could cut it with a knife

you could cut (something) with a knife

Something intangible or non-solid is incredibly thick, palpable, or poignant. The air was so humid as we stepped off the plane if felt like you could cut it with a knife. The entire dinner was so awkward you could cut the tension with a knife.
See also: could, cut, knife
Farlex Dictionary of Idioms.

you could cut it with a knife

Alluding to something very thick, such as muggy air or a heavy accent; also, a very tense atmosphere. For example, The smoke was so thick you could cut it with a knife, or When I walked in they all stopped talking and you could cut the air with a knife. [Colloquial; late 1800s]
See also: could, cut, knife
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • you could cut (something) with a knife
  • you could cut the atmosphere with a knife
  • buzz with
  • buzz with (something)
  • take an axe to
  • in the abstract
  • strive after
  • strive after (something)
  • strove
  • strike a chord (with someone)