combustibility vs combustibleness

combustibility and combustibleness both are nouns.

Word	Noun	Adjective	Verb	Adverb
combustibility	Yes	No	No	No
combustibleness	Yes	No	No	No

As nouns, combustibility and combustibleness are synonyms defined as:

combustibility and combustibleness: the quality of being capable of igniting and burning

Other synonyms of combustibility include burnability.

combustibility (noun)	combustibleness (noun)
the quality of being capable of igniting and burning	the quality of being capable of igniting and burning