Just learn the history of the word villain...well history is not the right word for what I am saying, etymology (origin of the word and then study of how words change throughout time) but etymology is one of those words that look scary on the internet due to all the latin and greek sounds and most people are not familiar with the meaning of the word etymology in daily life.

So the etymology of the word villain, lets do a little history first

Roman Emperor Diocletian is a guy who ruled the great Roman Empire from 284 to 305 AD (aka 20 years prior to the de-criminization of christianity by Constantine) Two important things that you need to know about him.

He is one of the big founders of bureaucracy as how we know bureaucracy to mean with the word today. He fundamentally reorganized Roman society and thus European society with laws, precedents, etc. He did this to simplify government for ruling the people was taking too much of his time.

He massively reformed the Roman System of government even though his predecessors were already doing so. Even the word precedent can be traced back to this guy for while precedent is an english word it is based off the latin word praecedentum which is just a fancy modified version of precede (english) / praecedo (latin) with pracedentum being how did we do it last time? Well lets do it similar to that and make that the general rule unless someone with authority (power to force obedience / change the rules / the original the zero but at the same time the omega) says we can make exceptions or lets change the general rule.

Tom if he reads this may say I am glossing over the most important parts on how Diocletian is foundational of the splitting of the roman empire to the Roman Empire and the Byzantine Empire but I do not know enough of this so I will let him explain it, or you just cust google it such as this link.

http://www.britannica.com/biography/Diocletian

One of his "reforms" was a fundamental restriction of liberty. Farm People were not allowed to leave the lands they lived in without permission of two people.

1) The person whose land they were currently living on aka their lord
2) The person whose land they are going to be moving to and thus the new place they would be farming on.

Moving and you were a farm hand / person (for back then people had rank unlike we do nowadays) without the permission of these 2 people means you were breaking the law.

So in sum Roman Emperor Diocletian is one of the foundational people that leads to Feudalism and Serfdom where you are living a life as a slave / sharecropper.

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So what do these words mean in latin you may ask

Villanus means farm hand in late latin, which in turn becomes the anglo/french word villein which in turn becomes villain.

Eventually villain though switches from a farm hand to a person whose is of low education and often of bad manners and bad taste. Aka a base or lowborn rustic or hic. We can call Luke Skywalker under this definition of the word villain (farm hand)

And around the 1800s finally the meaning of villain switches to someones whose interest opposes yours, or who is purposefully trying to fight against you, or is just a person who you can't identify on the battlefield but he is now dead and he appears to be shooting at your side and thus he must be a villain.

http://www.etymonline.com/index.php?term=villain

https://en.wiktionary.org/wiki/villain

https://en.wikipedia.org/wiki/Villain

Now this origin of the word villian as enemy or rival or scoundrel started to appear somewhat prior to the 1800s but it gain traction during this time.

What is different during that time? Well it had to do with the abolition of serfdom throughout the world. Serfdom and some other forms of slavery was pretty much outlawed in the really cold northern places with bad farming land like Sweden, Norway, Scotland in the 1300s and 1400s. Economics forced it to be unofficially over in England about 1500. European countries officially banned it from the 1750s to 1861.

The United States finally got rid of slavery 1865 though sharecropping an unofficially form of slavery still had lots of power till the great depression when the switch from farming being really labor intensive to machinery intensive fundamentally changed how farming was done. This occurred about the 1930s, after world war 2 it fundamentally went on hyperdrive. Oh it was not just the transition to more machinery, remember at the same time we had the depression and the dustbowl in some states which only further enhanced the more or less removal of sharecropping. That and the remaining workers were starting to collectively organize ... (that said the landowners did not really like that and tried to use violence to stop this.) Now sharecropping existed past the 1930s but the economy just fundamentally changed.

Oh sharecropping was not just a black thing though they were the most "hurt by it" due to Jim Crow. In 1930 5.5 million whites were sharecroppers, and 3 million blacks. The thing is with being a black sharecropper that was the only options while a white sharecropper may be able to break through the metaphorical ceiling and escape that lifestyle

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Now there is a "nicer word" that we use instead of the word villain in our history books while prior to 1800 the more common word used was actually the word villein.

That word is serf.

What does the word serf mean in latin. It means SLAVE

It also means slave, servant, serving man, and vassal (but in this sense vassal mean one who was obligated to serve his lord, and not vassal like a lord is a vassal to his king)

Somehow the word that meant farmhand became the insult while the word that mean slave somehow became a nicer and less pejorative way of saying the same thing. The one which means farmhand became a form of slang, a form of insult.

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Now lets bring this to modern times

So if we want to go way political (please feel free to skip this), any person we predator drone bomb to death and is a man of fighting age is now a villain under the modern definition and the definition that started to appear as the main definition in 1800s.

There is a term that is used in countries where the United States uses predators. Beware the Blue Skies... here is a testimony from

“I no longer love blue skies,” said Rehman a 13 year old girl and survivor of a predator drone attack to U.S. lawmakers (her surviving family testified it was not just her). “In fact, I now prefer gray skies. The drones do not fly when the skies are grey.”

http://www.wired.com/2014/04/tomas-van-houtryve-drones/

http://www.theguardian.com/world/2013/oct/29/pakistan-family-drone-victim-testimony-congress