The definition of gravity is, according to NASA: "The force of attraction that exists between any two masses, any two bodies." If you want proof of that, get a bowling ball raise any height and let that go. The bowling ball and earth, both are bodies, get attracted to each other. We can see this in still space as non-rotating massive bodies attract other bodies. Also light is bent around a star due to gravitational lensing, or the force of gravity on light.
This is based on hundred years of study! And this can be tested! Debate itself cannot prove this correct or wrong! This is natural science and we only look at facts! Only people who never learned and have no sense of math, science and technology would say No to this!
Gravity can not be seen, touched, tasted, smelled, heard, measured. Is gravity a name we gave to a unknown force that we do not fully know if it exist? We could be stuck to this earth by centrifugal force. Some people say gravity is a force, while others say it is an acceleration, some say it is both. We can not measure gravity if it is a force, but we know the a creation due to gravity. However for an acceleration you need a force that we still can not measure. So what is it?