Draco Malfoy 

Draco is Latin for dragon, ultimately the ancient Greek drakōn, meaning serpent. The first part, mal, should be easily recognised as meaning evil or bad. It shows up in English in such words as malevolent, malicious or malign, and comes from the Latin adjective “malus” meaning evil or bad.

Draco Malfoy

Blond hair is usually associated with innocence, and sometimes the stereotypical incompetency...

but in Malfoy’s case it makes him look slimy, and because it looks greasy it makes him look evil.

His slicked back hair signifies to the audience that he is a bad character, because even though the stereotypical villain hair colour is dark, because his hair is slicked back it reflects on his 'greasy' character, as well as it contrasts with his actual character, which is dark whereas his hair is light.

He looks like this because it emphasises his evil character, even if he's not entirely bad in the last film. 

Villain

Sly

Strange

Different

Noble

Aryan race (pure blood)

Cold

Creepy

Devious

Cunning

Shrewd

Astute

Machiavellian

Deceitful

Draco Malfoy - 1st year in Hogwarts