ok heres the deal. everytime a player wins a match and they get quite lucky and have 8-1 and 12-3 ,they get all excited and call their self pro and good and call other enemy team noobs and keep saying Umad? ,But when i check their match history they plain suck and have nothing but defeats. what do u call these peoples?

Noobs? Poor Sports, Sore Winners (Personal Favorite)

Scrubs? Scabs, Posers maybe

Ideally you say nothing, knowing that you are correct in your stance when you check their match history. Proving this to the person still gets both parties nowhere, sometimes people will feel the need to gloat about their victory.

If you feel that this provides an unfavorable experience for you than you have the option to report this person and know you have done all you can to avoid others from experience this negative behavior.

-RyuTres

If they are prominent losers, but usually have high scores, they are likely a-holes who don't support the team. If not, they are noobs who just got a nerd woody. I've seen a game where the enemy Yi had 25 kills, but around 15 deaths, and rest of the team didn't get more than 3 kills. Needless to say we were mostly positive and won with little difficulty. We got into a team fight pushing their mid inhibitor turret and I look on the map to see Yi soloing our top second turret. Sure he killed the turret, but big whup, it was still a defeat for him. If they are sincerely a good player they may banter a little bit, but only in a joking sense. When I do good I give the usual GG and show up in post game chat but I usually just let my lane opponent know it was a good match and that they were a good opponent (when they are), I can't stand people who trash talk post game, almost as much as I can't stand people who troll around during the champ selection.

Yeah, some trash talking is kind of funny. Like when a Pantheon does Grand Skyfall and gets a quadrikill. Sometimes that deserves a little banter. XD

Edit: Or when you are playing with 4 of your friends and troll them all by using your abilities to push all 4 into the double turrets at enemy nexus :S

Recently, i've been ignoring EVERYONE at the beginning of games. This is because in ranked, I jungle .. and when the game goes downhill, its automatically the jungler's fault. ALWAYS. So, when you find someone like that, just be sure to add him / her to your ignore so you never have to play with them ever again. n.n

You call them typical LoL players

Like the Riot guy said, just use the report function, that's what it's for. It's probably a good idea to remind such players that they have a duty to be pleasant, help newer players and keep swearing & verbal abuse to the barest of minimums. If you think that this isn't your cup of tea, or will just makes things worse, then just ignore such people in-game.

Sadly, because young kids play LoL, there will always be some people who get nasty with the other team when they're winning, or who insult their own team when they're losing. Over time, hopefully such players will be weeded out or reform their behavior. It's such a great game to play, and requires the basic principles of teamwork to be successful.