Flammability is a chemical property.

Capable of igniting and burning is a combustible gas.

Any compressed gas meeting the requirements for lower flammability limit, flammability limit range, flame projection,etc.

All flammable substances are surely combustible, but all combustible substances are not essentially flammable.

flammability is how easily something can catch fire

Flammability is a physical chemical property of materials.
Flammability is a chemical property.

Thermability