Villains

To research into what makes villains villains I have done some research into the history of the term.
To start with, this is the kind of definition that I understand as a villain (courtesy of Dictionary.com):

vil·lain

   [vil-uhn]  Show IPA

–noun

1.

a cruelly malicious person who is involved in or devoted towickedness or crime; scoundrel.

2.

a character in a play, novel, or the like, who constitutes animportant evil agency in the plot.

These two definition sum up perfectly what a villain is, but in terms of my Top 10 video they have a much more light hearted side to them. After all, the villain rarely wins so there is never too much of a sense of danger about them and they can't be taken too seriously.

The term Villain itself is derived from the old french word 'Villein' which again is derived from the Latin 'Villanus' which was a term for a farm hand, more literally someone who worked on the grounds of a villa (the modern day equivalent being a plantation) in Italy or Gaul. People considered 'Villanus' had a less than knightly status and so were not chivalrous.
Acts such as murder, rape and theft obviously quickly became known for not being chivalrous and as such started to become associated and defined as the modern term 'Villainous' and so the word picked up the connotations of abuse and wrong doing.

Vladimir Propp:

I remember from A level Media Studies that Vladimir Propp (A Soviet scholar who analysed russian folk tales among other things) defined all the characters that could constitute a fairy tale or similar story; Villain being a primary character.
The list of 8 characters is like this:

1. Villain - Struggles against the hero
2. Donor - This is the character who send off (tests) the hero
3. Helper - (Possibly magical) Helps the hero in their quest
4. Princess/ Prize - The goal that the hero strives for. The story usually ends at the point that he marries/ obtains the prize. 
5. Her Father - Send the hero on the quest, Identifies a false hero, marries the hero. Propp notes that the father and the princess 'can not be clearly distinguished'. 
6. Dispatcher - Prepares the hero or gives the hero a useful/ magical object.
7. Hero - Reacts to the donor (or similar character), weds the princess/ gets the prize. 
8. False Hero - Takes credit for the hero's actions/ tries to marry the princess. 

Similar to this, I remember theories of what constitutes a story put down in the most basic terms:

• Equilibrium - Everything is fine and normal
• Disruption - Something happens to break the equilibrium and cause crisis (villain)
• Realisation - The main character (hero) realises the disruption and sets about  restoring order
• Action - Some actions take place to try and reinstate equilibrium
• New Equilibrium - Everything goes back to the way it was or at least changes to a better state. 

This is the basic narrative structure according to Tzvetan Todorov. If you look at each of these steps very broadly you can see that they fit to most stories and it is clear how the characters of Propp's theory can fit into place.

As for the modern interpretation of a villain, it has definitely taken on a much less disturbing form, probably because of things like cartoons in which villains are commonly exaggerated characters with no real sense of peril. Here is a classic image of a modern day villain:

It may also have to do with post modernism in the form of things like parodies in which classic villain flaws and cliches are pointed out. 

Either way the image of a villain and actions that constitute their behaviour have changed dramatically from a historical point of view.