The phrase "massive sunroof" refers to a very large and wide opening on the roof of a vehicle that lets in a lot of sunlight and gives a feeling of openness inside the car. Full definition
VW's infotainment is seamless as always, and that massive sunroof makes the cabin seem bigger than it is. (autofocus.ca)
Its massive sunroof had me sitting back in awe at the stoplight as I soaked up the sun kissing my face... that was until the idiot behind me decided to break the mood with his horn. (automobilemag.com)
For those days when it's too hot or too wet or too cold to lower the roof, the massive sunroof provides light or fresh air without fully exposing you to the elements. (automobilemag.com)