hydrocephalic vs hydrocephalus

hydrocephalic is not a noun while hydrocephalus is a noun.

Word	Noun	Adjective	Verb	Adverb
hydrocephalic	No	Yes	No	No
hydrocephalus	Yes	No	No	No

hydrocephalic (noun)	hydrocephalus (noun)
	an abnormal condition in which cerebrospinal fluid collects in the ventricles of the brain; in infants it can cause abnormally rapid growth of the head and bulging fontanelles and a small face; in adults the symptoms are primarily neurological

hydrocephalic (adjective)	hydrocephalus (adjective)
relating to or characterized by or evidencing hydrocephalus