I have to add something to the word of the day, because I feel that there is something missing in the explanation given by AWAD - at least for English speakers.
The first meaning of "spogliare" coming in my mind is "to undress" - from this meaning the others meanings come in this way : after a battle, the winners take all the clothes - and, by extension, all the valuable things - of the losers, leaving them naked and without anything...from this idea, the meaning of plundering.

To the victor belong the spoils. Like Hannibal's bushel of Roman signet rings after Cannae.And losing knights in battle being stripped of their armour.
But the principal victim today is the environment being spoliated by clear-cut logging, pit mining, and massive pollution.

Thanks for that interesting context, Emanuela. Am I right, o Latin scholars, that the English spoil comes from ME spoilen (via pardon my French) from the Latin spolium meaning plunder or booty?

Hmmm - this is interesting. This means that, if you are right, mav (and I have no reason to believe otherwise) "spoil", strictly speaking, means to make something unuseable or unattractive by taking things away from it.
Which is far from the frequent, modern usage, where you can spoil your picture by ADDING too much paint, or spoil your shirt-front by adding indelible ink (or curry paste - much the same thing in far too many English restaurants!)