irritable vs pathology

irritable is not a noun while pathology is a noun.

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

irritable (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

irritable (adjective)	pathology (adjective)
easily irritated or annoyed
capable of responding to stimuli
abnormally sensitive to a stimulus