Someone who smiles in a way that shows they do not respect someone or something.
The word 'sneerer' makes people think of someone who is not nice and who looks down on others.
Examples:
The sneerer looked at me and laughed.
I don't like being around sneerers.
The sneerer made fun of my shoes.
The sneerer thinks they are better than everyone else.
The sneerer always looks at people like they are not good enough.
The sneerer's smile made me feel bad about myself.