The Collaborative International Dictionary of English v.0.48:

Pirate \Pi"rate\, v. i. [imp. & p. p. Pirated; p. pr. & vb. n.
   Pirating.] [Cf. F. pirater.]
   To play the pirate; to practice robbery on the high seas.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pirate \Pi"rate\, v. t.
   To publish, as books or writings, without the permission of
   the author.
   [1913 Webster]

         They advertised they would pirate his edition. --Pope.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pirate \Pi"rate\, n. [L. pirata, Gr. ?, fr. ? to attempt,
   undertake, from making attempts or attacks on ships, ? an
   attempt, trial; akin to E. peril: cf. F. pirate. See
   Peril.]
   1. A robber on the high seas; one who by open violence takes
      the property of another on the high seas; especially, one
      who makes it his business to cruise for robbery or
      plunder; a freebooter on the seas; also, one who steals in
      a harbor.
      [1913 Webster]

   2. An armed ship or vessel which sails without a legal
      commission, for the purpose of plundering other vessels on
      the high seas.
      [1913 Webster]

   3. One who infringes the law of copyright, or publishes the
      work of an author without permission.
      [1913 Webster]

   Pirate perch (Zool.), a fresh-water percoid fish of the
      United States (Aphredoderus Sayanus). It is of a dark
      olive color, speckled with blackish spots.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pirate
    n 1: someone who uses another person's words or ideas as if they
         were his own [syn: plagiarist, plagiarizer,
         plagiariser, literary pirate, pirate]
    2: someone who robs at sea or plunders the land from the sea
       without having a commission from any sovereign nation [syn:
       pirate, buccaneer, sea robber, sea rover]
    3: a ship that is manned by pirates [syn: pirate, pirate
       ship]
    v 1: copy illegally; of published material
    2: take arbitrarily or by force; "The Cubans commandeered the
       plane and flew it to Miami" [syn: commandeer, hijack,
       highjack, pirate]

The Free On-line Dictionary of Computing (19 January 2023):

software pirate
pirate

    Someone engaged in software piracy.

   (2010-02-03)