Flammable has a very specific definition - it must be easily ignited at room temperature. Kerosene is not easily ignited at room temperature (e.g. you couldn't

Flammable has a very specific definition - it must be easily ignited at room temperature. Kerosene is not easily ignited at room temperature (e.g. you couldn't light a puddle of it with a match), so it is not considered "flammable". It does burn at room temperature though, so it is considered "combustible"