piracy

Short definition from Wiktionary

Noun

1. 1
   Robbery at sea, a violation of international law; taking a ship away from the control of those who are legally entitled to it.
2. 2
   A similar violation of international law, such as hijacking of an aircraft.
3. 3
   The unauthorized duplication of goods protected by intellectual property law.
4. 4
   The operation of an unlicensed radio or television station.
5. 5
   Kleptoparasitism.