Depends. Will your site be dealing with the same subject manner as the already existing site? If so, then they are going to claim first use in commerce, especially if they own a trademark or have started a small business around it.
it is a adult date website also i will start a adult date website but my website is with different features.
You will have a problem if the name is trademarked but general they are not, you will need to check. You can also get that sort of advice from the domain regulator in your country.