fistulous vs pathology

fistulous is not a noun while pathology is a noun.

Word	Noun	Adjective	Verb	Adverb
fistulous	No	Yes	No	No
pathology	Yes	No	No	No

fistulous (noun)	pathology (noun)
	the branch of medical science that studies the causes and nature and effects of diseases
	any deviation from a healthy or normal condition

fistulous (adjective)	pathology (adjective)
of or pertaining to or resembling a fistula
hollow and tube-shaped like a reed