In its most general sense, spoliation just means the act of spoiling or wrecking something, from the Latin spoliare, to spoil. It's more usually used to mean plundering or pillaging, especially during war - plunder and pillage generally having a wartime connotation. Spoliation also refers to the seizure of neutral ships at sea during hostilities. Finally, there's the legal meaning, the deliberate destruction or alteration of a document. You know, like Nixon authorized.