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know full well | know perfectly well

This page is about the conversational phrase know full well | know perfectly well

Meaning

You can say this if you're sure someone knows something when they're pretending not to.

For example

  • When my son said he didn't know anything, I said "You know full well what I'm talking about!"

  • I went back to see the shopkeeker who'd cheated me. "Don't try to look surprised," I said. "You know perfectly well why I'm here."

Quick Quiz

You can say "You know full well what I'm talking about" if someone's

a. pretending to know

b. pretending not to know

c. pretending not to know you

Contributor: Matt Errey