rheumatoid vs rheumatic

rheumatoid is not a noun while rheumatic is a noun.

Word	Noun	Adjective	Verb	Adverb
rheumatoid	No	Yes	No	No
rheumatic	Yes	Yes	No	No

As adjectives, rheumatoid and rheumatic are synonyms defined as:

Other synonyms of rheumatoid include arthritic, creaky, rheumy.

rheumatoid (noun)	rheumatic (noun)
	a person suffering with rheumatism

rheumatoid (adjective)	rheumatic (adjective)
of or pertaining to arthritis	of or pertaining to arthritis