The act of laying waste to something or stripping it of its valuables is suggested by all these words. Plunder suggests, most specifically, the roving of armed men through recently conquered territory in search of money and goods: generals who permitted the city to be plundered while the inhabitants cowered behind locked doors. It can also be applied to the sizing of anything by force or fraud: innocent victims plundered of their life savings by fake cancer cures. It can suggest the devastation of something for financial gain: timber speculators who plundered irreplaceable forest lands. It is also used as a hyperbole for any act of depleting: recklessly plundering our liquor cabinet.

Pillage is less common and more formal than plunder and is restricted to the act of stripping conquered people or lands of money and goods during wartime: Visigoths who pillaged cathedral and synagogue without discrimination. In extended usage, the word may refer to any unscrupulous swindle or self-serving theft: He pillaged other writers and appropriated whole passages.

Sack is more extreme than pillage , not only implying the seizure of all valuables but usually suggesting wholesale destruction as well. A strong word, it is typically restricted to a context of war: the Greeks who sacked Troy; Nazi armies sacking Europe’s art galleries. Ravage means to lay waste or wreak havoc, as by pillaging or burning. The word has fewer implications of a search for valuables than sack and has a great many figurative uses suggesting devastation: samurai who ravaged the surrounding towns and farms; the disease that ravaged his body; open-pit mines that ravaged the countryside.

Loot might once have been exactly synonymous with those meanings of plunder and pillage restricted to the context of war, but it now more commonly suggests the seizing of valuables by theft or riot, especially when these forays are hasty, disorganized or even aimless: looting the museum of two valuable paintings and destroying five others; bands of teenagers who broke store windows and looted the displays.