Is oneclicktvshows safe?

There's nothing to say that oneclicktvshows will directly do your computer any harm, however, these types of sites may slow down your computer, or even infect it with a virus, so it is probably a good idea to make sure you have comprehensive anti-virus protection if you are going to be using the site a lot.

The problem with these types of sites is that they usually have a lot of running processes that we can't see, along with pop ups and potential malware.

There are also the legal implications of using onelicktvshows. It is a violation of copyright law to stream or download TV shows outside of regulated channels, and in some countries ISP's will provide details of such activity to the producers of the show, and will issue you a copyright infringement notice.

If you are willing to run the risk- and in all honesty it is probably quite small, most copyright infringements are issued for music rather than TV- then don't worry, but if you'd rather do things legally, then maybe try Amazon Prime or Netflix instead.