flamable,inflamable,non-inflamable...why are there three?

I mean the thing either flams or it doesn't flam

 

Surely non-inflamable is different!

From dictionary.com

Inflammable and flammable both mean “combustible.” Inflammable is the older by about 200 years. Flammable now has certain technical uses, particularly as a warning on vehicles carrying combustible materials, because of a belief that some might interpret the intensive prefix in- of inflammable as a negative prefix and thus think the word means “noncombustible.” Inflammable is the word more usually used in nontechnical and figurative contexts: The speaker ignited the inflammable emotions of the crowd.

 

Off the top of your head mate?

 

No

Hence the reference to dictionary.com

 

habited, unhabited, inhabited, uninhabited

And of course, "in this world in which we live in"