Why does "spoil" account for both

Why does "spoil" account for both
The worst and for the best?

i.e.
That food is spoiled
&
Tonight i'm gonna spoil you he whispered to the girl.

you are the spoils of war and is about to be raped

I don't understand

Sometimes words have more than one definition.

I can't think of another with opposite definitions

Pretty simple desu. You can think of it as spoil as in the Latin "to rob", or spoil as in to give the thing that was taken. So if it spoils something is taken from it,while if it is poiled something is given to it. Works in both respects, just depends on context

The verb 'cleave' can mean to split something in two, or to stick two things together.

nonplussed means that someone has been rattled, or unaffected. Since I used to learn most new vocab by context, nonplussed confused me for years.

Didn't know it had latin roots

Yeh, that's one of those Americanisms where they change the meaning of something entirely. Like when they say they "could care less" to imply that they could not, in fact, care less.