nymphomaniacal vs nymphomaniac

nymphomaniacal is not a noun while nymphomaniac is a noun.

Word	Noun	Adjective	Verb	Adverb
nymphomaniacal	No	Yes	No	No
nymphomaniac	Yes	Yes	No	No

As adjectives, nymphomaniacal and nymphomaniac are synonyms defined as:

nymphomaniacal and nymphomaniac: (used of women) affected with excessive sexual desire

nymphomaniacal (noun)	nymphomaniac (noun)
	a woman with abnormal sexual desires

nymphomaniacal (adjective)	nymphomaniac (adjective)
(used of women) affected with excessive sexual desire	(used of women) affected with excessive sexual desire