Meaning of cocked hat

cocked' hat'

Pronunciation: [key]
  1. a man's hat, worn esp. in the 18th century, having a wide, stiff brim turned up on two or three sides toward a peaked crown. Cf. bicorne, tricorne.
  2. to destroy completely; render unachievable.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.