Pillage and plunder are closely connected, almost tautology. In common use they have come to be separated with pillage being used, often, in the sense of wanton destruction and plunder the taking of valuables, both connected with violence.
But language mutates, often in the hands of those that are unused to historical connotations.
And so Philippines pirates and illegal invaders based in the Southern Philippines form bands of marauders to attack Malaysian Borneo, with hearts set on occupation, kidnap, pillage and plunder.
But in Philippines law, "plunder" means something completely different.
There it is the illegal acquisition of state assets, a term to fill in the gaps between bribery and corruption: it goes beyond embezzlement. It's where those in office simply take what they want from the state which, because The Philippines is a republic, means to take it from the people.
"Plunder" is the charge levied against former presidents including Ferdinand Marcos, removed from office in 1986 and whose stolen wealth remains, in large part, undiscovered and unrecovered.