It is usually used for people who allegedly hate or dislike someone out of jealousy.

1. A person that simply cannot be happy for another person's success. So rather than be happy they make a point of exposing a flaw in that person. Hating, the result of being a hater, is not exactly jealousy. The hater doesnt really want to be the person he or she hates, rather the hater wants to knock somelse down a notch. 2. Overused word that people like to use just because someone else expresses a dislike for a certain individual. 3. A person who feels anger and/or jealousy for someone who has succeeded in something they have worked hard for. A being who speaks badly,and/or takes negative actions in attempt to create problems for a successful person. 4. A label applied to people who are more negative than positive when discussing another person. It most commonly refers to individuals whose negativity is so extreme that it is all-consuming. However, there are various levels and forms of being a hater, ranging from completely dismissing any positive traits or actions, to merely painting a less than flattering picture by using words with negative connotations. Hating is often attributed to jealousy, but just as often, it seems to stem from some other source. 5. One who either verbally and/or physically inhibits another individual's game or mode of operation primarily due to jealousy, envy, animosity, bitterness, resentment, and contempt. A hater will exibit either one or all of the aformentioned traits. A hater will usually smile in your face and hate behind your back. http://www.urbandictionary.com/define.php?term=hater

They hate them.

The word " Hater " is bigger than people think and it gets tossed around to easily .. Hater means that a person does not like something , could be liver ex ... Todays people just toss it around like it's a ball of fire and that is what they hope it will do , stir up crap for no good reason .. people should like what they like and not like what they don't like without being bashed to death ... I am a big hater toward child molesters , yes you bet ..