If the meaning behind the term "responsive website" is unfamiliar to you, you're more than likely in the majority. Let's start with some background information, for those who aren't familiar with this fairly new functionality.
Responsive websites adjust automatically to fit on desktop, tablet and smartphone browsers. In the past, you've probably opened a website on your smartphone and it was a miniaturised version of what you would see on your desktop. You zoomed in and then moved the website around and enlarged and zoomed out as needed, to read text and click on things. That was not a responsive website. A responsive website looks good whether you're looking at it on a phone, a tablet, or on a desktop. In fact, you're reading this post on a responsive website - if you're able to, open this page in a desktop browser and also a tablet (portrait or landscape) or a smartphone, and you'll see the subtle changes that are programmed in so that the site displays in an appropriate format on the screen, and orientation, of choice.