knock dead

knock (one) dead

To strongly impress one. Often used as an imperative to give encouragement. Good luck on the audition! Knock 'em dead, kid! Your design is going to knock the judges dead. They're going to swoon over it.
See also: dead, knock
Farlex Dictionary of Idioms.

knock dead

Greatly amuse, astonish, or thrill someone, as in This new song will knock them dead. This slangy hyperbolic expression was first recorded in 1889. Also see knock the socks off.
See also: dead, knock
The American Heritage® Dictionary of Idioms by Christine Ammer.

knock dead

1. To kill with a blow.
2. Slang To affect strongly and positively: a performance that knocked the audience dead.
See also: dead, knock
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • knock (one) dead
  • knock 'em dead
  • knock somebody dead
  • knock someone dead
  • knock about with (one)
  • knock up
  • knocked up
  • knock (someone) down with a feather, to
  • knock one back
  • knock something back