anorexia nervosa vs anorexia

anorexia nervosa and anorexia both are nouns.

Word	Noun	Adjective	Verb	Adverb
anorexia nervosa	Yes	No	No	No
anorexia	Yes	No	No	No

As nouns, anorexia is a hypernym of anorexia nervosa; that is, anorexia is a word with a broader meaning than anorexia nervosa:

anorexia nervosa: (psychiatry) a psychological disorder characterized by somatic delusions that you are too fat despite being emaciated
anorexia: a prolonged disorder of eating due to loss of appetite

anorexia nervosa (noun)	anorexia (noun)
(psychiatry) a psychological disorder characterized by somatic delusions that you are too fat despite being emaciated	a prolonged disorder of eating due to loss of appetite