Spoil, plunder, booty, prize, loot, swag can mean something of value that is taken from another by force or craft.
Spoil applies to the movable property of a defeated enemy, which by the custom of old-time warfare belongs to the victor and of which he strips a captured city or place. With changes in methods and customs of warfare spoil, and especially its plural spoils, tends to be applied not only to property or land taken over by conquering forces in actual warfare or demanded by them from the conquered as a condition of making peace but also to whatever by custom and often unethical custom belongs to a victor whether in warlike endeavor or more peaceful pursuits; thus, in political use spoils applies chiefly to appointive public offices and their emoluments which the successful party in an election regards as its peculiar property to be bestowed as its leaders wish. But spoil may also apply to something gained by skill or effort or sometimes acquired as casually as if by looting.
Plunder implies open violence (as of marauders) and is a more inclusive term than spoil because not restricted to warfare; it consistently implies robbery, whether as incidental to war or as dissociated from it and is applicable to what has been seized not only by spoilers, pillagers, and sackers but by such ruffians as bandits, brigands, and highwaymen.
Booty, like plunder, is applicable to martial spoils as well as to what is seized by or as if by robbery or theft.
In international law booty is technically used in distinction from prize, booty referring to spoils taken on land, and prize, to spoils captured on the high seas or in the territorial waters of the enemy.
Loot may be used in place of plunder, booty, or spoils when a highly derogatory or condemnatory term is desired.
The term is also applied specifically to the plunder of those who rob the dead or helpless victims of a catastrophe or who steal anything left of value in the ruins of buildings wholly or partly destroyed (as by fire, flood, earthquake, or violent storm).
In more general use the term is applicable to gains felt as ill-gotten.
Swag is also often used in place of loot or plunder especially to imply a collection or sackful of valuables gathered by or as if by thieves.