What does Overlimit mean?
If you pass over the accepted credit limit, that is called overlimit. It always depends on the issuer (banking institution) whether when you want to make a purchase which would actually throw you over the limit, he will deny the transaction or he will charge you a huge extra fee. Especially if you are a card holder who happens to run over the limit more times a year, a good option for you would be to ask for a higher credit limit, so that you will not be charged these fees.
However, you might be put into a vicious circle, because as your credit limit raises, your expenditures will raise as well, which will eventually lead you again to overlimit. So, carefully weigh the options, and try to stay economical and not spend over the admitted limit. Spending habits die hard but everything is actually up to your own will power.