any person, place, or thing that encourages a hater to hate

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

A word that is often used to refer to racists, sexists, etc. But really just means anyone shallow, selfish, spiteful, unforgiving, and who generally has their head up their ass. Racists and homophobes are not necessarily "hateful". The word you're looking for is "bigot".

To show one's emotion in a rude demeanor to another, expressing distaste, displeasure or hate for one.

to be mean,a butt-hole,grumpy,to someone for no reason