noun

• (nautical) A ceremonial dagger worn by naval or air force officers in some nations' militaries; formerly, a fighting dagger used by sailors as a boarding weapon.
  "In half a minute he had reached the port scuppers, and picked, out of a coil of rope, a long knife, or rather a short dirk, discolored to the hilt with blood."

verb

• (obsolete) To darken.
  "Thy wast bignes but combers the grownd, / And dirks the beauty of my blossomes rownd."

noun

• (Midwestern US, dated, slang) A penis.
  "The word dick itself serves as model for two variants which are probably Midwestern, dirk and dork, also meaning "penis"..."
• (Midwestern US, dated, slang) A socially unacceptable person; an oddball.
  "Near-synonym: dork"