Someone who is really everything they try to make fun of, while imitating everything they are while trying to make fun of somebody.
The poser had to wait on somebody else to come up with material so she would have something to say was not theirs originally.
If a guy has convinced people he's Italian (such as an actor in a movie), but he's not really Italian, no matter how believable the guy is, he's not authentic, so he's a poser.
The poser had convinced people that he/she was from hell and that he/she was hell, but since there was no hell, he/she was just another otherwise obscure poser.
Someone who is not who they say they are.
Even if he/she filed his/her teeth down into serrated edges and wore black contacts, he/she still wouldn't have anybody convinced that he/she was really a shark. He/she was a poser, posing as a man eating denizen of the seas.
Someone who's not who they say they are, or who they appear to be.
He/she was a poser because the person he/she was posing as might actually be missed by a few people.
Someone that thinks a team wants to be like another team because the other team has the better record. Nobody likes to lose, but would you rather lose as you or win as somebody else? It doesn't take any honor to win.
If you're not fighting as you, what's the point of being undefeated? People wouldn't allow their team to lose without a fight, but before they wouldn't let them lose, they wouldn't let them become a poser team. They would rather their team be losers or underachievers who were themselves than to be overachievers who were somebody else, even if it seemed stupid to everybody else.
Someone who's not really a troublemaker, but wants more than anything in the world to be accepted by the world, so does everything a troublemaker would do, thinking that being one is the answer to the question of what's wrong. A mama's boy or mama's girl posing as a rebellious teenager their entire life, well after their eighteenth birthday.
The boy/girl couldn't stop being a poser.
Someone that implies (or says) that because their hair or skin is darker than yours, that they are tougher than you by default, even if they are from further outside a city than you are, or have more money than you do.
There are posers who are from a city, and there are posers who are from outside a city. Some have fair skin and hair, some have dark skin and hair. So really it's a matter of more than just where somebody is from alone.