Tattletale - "a person, especially a child, who reveals secrets or informs on others."

Immature - "having or showing emotional or intellectual development appropriate to someone younger"

Childish - "of, like, or appropriate to a child."

Crybaby - "a person, especially a child, who sheds tears frequently or readily."

After reading these definitions, you could most likely immediately think of someone in any workplace you have been in that fits these definitions to a tee. They may fit one or they may fit all of them. After having an encounter with one of these people, you are probably annoyed and don't want anything to do with them either inside or outside of work. Unfortunately, the inside of work thing you can't do much about. However, there are some tips things you can do to help eliminate the annoyance that person has become.

Avoidance

Distance yourself. Ignore them completely if you can, unless it is something work related of course. But you are not at work to be their best friend. Do what you need to get done and nothing more. Avoid conversations entirely if at all possible. When it comes to tattletale they are going to find anything they can to go to your boss about so just be careful with your actions. If you do need to talk to them make sure it is nothing incriminating.

Confrontation

Whether they continue to tell on you, if they are talking about you behind your back, or if they are bullying you in some way, you have the right to confront them. You have to do this tactfully. You cannot go up to them in front of all your coworkers and scream at them and belittle them, it will not do any good. But you can talk to them privately in a calm manor and politely try and work out whatever the issue may be. Like I said earlier, you have to be careful about what you say so you are not incriminating yourself in any way.

Follow the Chain of Command

In any organization there is a chain of command for workplace complaints or problems. Make sure that you are following the chain of command. For example, if you have a problem with your coworker, you are not going to go straight to the CEO of a company. If you have an issue with your coworker, you go directly to them. If the problem is not resolved, then you can go to your supervisor or whoever is right above you. It is very unprofessional to skip the chain of command. Hopefully your coworker is mature enough to follow the chain of command themselves.

There are multiple types of people in the workplace. Whether you are dealing with someone who is immature, childish, a crybaby, or a tattletale, or maybe all of these wrapped in one, the most important thing to remember is just to focus on your work. Do not to anything that could get you in trouble with your boss or cause them to look into your work. If you are doing well in your work, the difficult coworker can't do anything to cause a problem for you. The key here is to focus.