Low-life is a person who has not evolved past the level of primordial ooze in the scheme of things. A low-life is an opportunist and has no guilt over doing rotten or heinous things. If they hurt the innocent or the naive of course a low-life will blame their victim for not being as low-life as they are.
One who posts the names of people they don't like on Urban Dictionary and uses it to deride and/or harass them because they are too afraid to confront them in actuality.
a person who has no future, has two felony charges, has no means of trasnportation, distributes illegal drugs, someone that is with a chick with a kid by a different guy