Not at all
yes
Combustable liquids burn, all of them. Non combustable liquids, not so much.
fossil fuels
Yes.
Water can be a product of combustion.
combustable
Only in extreme heat.
Phosphorus is combustible which means that it is flammable.
A combustable engine
Sometimes there are gases that are combustable.
if its combustable it releases energy when it burns
No, however they can be combustable when compressed or mixed with air.