What is the difference between gravitational mass and inertial mass?

Ok guys here’s a real screw ball. I’ve thought about this a bit but would like to see what others think. So I’d like to hear from all of you: non-physicists, armchair physicists, amature physicists, physicists without degrees, and physicists with PhDs.
The problem: the mass term used in Newton’s laws of gravitiation is not necissarily the same as the mass term used in his second law of motion. If they are different why? If the are the same why?