Understand what you want out of the game.
There are so many different ways to play tabletop RPGs. Is your intent to offer a silly adventure where the main goal is to just have fun for a few hours, or do you want to have a serious narrative experience for your players to take seriously? There are no wrong answers here, but it helps to have a clear image of what you as a GM want from your game.
Ensure there really is a problem at your table.
While it may look like a problem to your eyes, ask your players. Do they mind that the player is cursing? Do they mind that they're using their knowledge to be more effective at the game? While being concerned for your players is a good trait to have and if they have a problem with it then by all means try to resolve the issue, it's ultimately not your job to determine if someone is a "bad influence" nor is it to try and keep your other players away from it.
Keep in mind your own views on these aspects are important as well, but there are cases where what seems to be a problem are in fact fine. We have a player at our table who almost never talks or voices up, which at a glance seems to be a problem that the other players aren't letting them get a word in edge-wise, but in reality they just enjoy listening to the narrative being told and are quite enjoying themselves. Ensure a similar situation isn't the case at your table first, and that the other players aren't enjoying seeing the things that can be accomplished by this player.
Exploiting can mean a host of different things, but they all fall into the same general categories. In Pathfinder's case (Assumption based on your previous question) if they're using their abilities in unique ways to circumvent challenges then great, finding alternate ways to complete challenges is part of the charm of playing. If they're arguing about rules and insisting they can get something done a certain way, remember that you as the GM are the final arbitrator of what goes and doesn't go, and if you see it as a gross misuse of power then you can make the call that it fails. Just ensure that your rulings are consistent and fair for all players involved to maintain a sense of trust and respect at your table.
What can you do?
Talk to the group.
Communication is the single most important aspect of tabletop RPGs. These games are social constructs by nature and at the end of the day it's all of you as friends coming together to have fun. If you see a problem arise at your table, talk to everyone about it, get their opinions on the events, and ask that moving forward they keep in mind courtesy and respect for their fellow gamers. Don't single out any individuals with a group talk. If you can't discuss a topic at your table without calling an individual out or making someone feel targeted, it's better left as a private conversation. (As detailed below).
Talk to the individual.
If an individual is hindering someones enjoyment at the table, whether yours or your players, pull them aside for a private conversation, or better yet talk to them between games. Let them know the potential issues you see arising at the table, and hear what they have to say. Maybe they didn't see it as a problem, or weren't aware of what they were doing.
In any event, discuss your concerns politely and calmly, use phrasing such as "I feel like..." or "If this is going to continue, We need to..." instead of "You're doing X wrong" or "You need to do Y/not do Z". Oftentimes this will be much more effective at letting them know they're impacting other players and they need to change their ways.
That didn't work, they're still a problem!
Sometimes players just won't change, they play how they play, act how they want, and that's it. If this happens there's a few possible solutions. If they continue to ignore your words and be a nuisance at the table then call for a 5 or 10 minute break. If it keeps happening, cancel game for the night. This is intrusive upon the other players at the table and shouldn't be attempted unless absolutely necessary, but it will get the point across that you won't tolerate one player's actions negatively affecting the rest of the group.
If they still continue to be a problem at the table, then consider dropping them from your game. Not every person is compatible at every table, and sometimes compromises can't be reached, and that's okay. Tell them politely that the difference in what the two of you are looking for is too great, and wish them luck in finding a table better suited to their tastes.
What NOT to do.
- Don't force your players to roleplay seriously. What their character does or does not do is the one and only choice they get to make in your entire world. That's not to say however that there won't be consequences for them kicking down a door instead of sneaking in or some alternative, an entire dungeon being alerted and rushing to overwhelm the party makes for a good deterrent.
- Never assume anything about your other players. If you suspect they have a problem, talk to them about it in private. Like everywhere else, communication is key here.
- Don't get aggressive or vindictive at a problem player in-game. If they're doing something in-game that you don't like, talk to them about it. All problems can and should be solved away from the table, out of the game. Unfairly targeting a player in the game only leads to mistrust and resentment
- Don't single anyone out. This leads to players feeling attacked, and oftentimes hurts the relationship and trust between player and DM more than it helps.
In the future.
Consider having a Session 0 about your game and game world to alleviate these kinds of problems in future games. Talk about any expectations in terms of tone you want within the game, etiquette around the table, and anything else of note. This helps to set a tone for your table and stop certain behaviors before they start.