masked ball vs mask

masked ball and mask both are nouns.

Word	Noun	Adjective	Verb	Adverb
masked ball	Yes	No	No	No
mask	Yes	No	Yes	No

As nouns, mask is a hypernym of masked ball; that is, mask is a word with a broader meaning than masked ball:

Other hypernyms of masked ball include ball, formal, masque, masquerade, masquerade party.

masked ball (noun)	mask (noun)
a ball at which guests wear costumes and masks	activity that tries to conceal something
	a covering to disguise or conceal the face
	a protective covering worn over the face
	a party of guests wearing costumes and masks

masked ball (verb)	mask (verb)
	put a mask on or cover with a mask
	shield from light
	cover with a sauce
	hide under a false appearance
	make unrecognizable