Origin: 1595–1605; < ML
inflammābilis, equiv. to L
inflammā(
re) to
inflame +
-bilis -ble 
Related forms: in⋅flam⋅ma⋅bil⋅i⋅ty, in⋅flam⋅ma⋅ble⋅ness, noun
in⋅flam⋅ma⋅bly, adverb
Synonyms:
2. fiery, volatile, choleric.
Usage note:
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.
[in-flam-uh-buh