Waterproof refers to the fabric’s ability to resist penetration of water. It’s creating a barrier between the elements and yourself.
Water resistant resists the penetration of water at low levels – it’s enough for light drizzle – but water will get through if pressure is applied to the fabric, for instance by a backpack strap.
Windproof is the fabric’s ability to resist the penetration of air. It can be done through the construction of the fabric or it can be achieved through applying a windproof membrane or coating to the fabric.