mask vs concealing

mask and concealing both are nouns.

Word	Noun	Adjective	Verb	Adverb
mask	Yes	No	Yes	No
concealing	Yes	Yes	No	No

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

Other hypernyms of mask include concealment, hiding.

mask (noun)	concealing (noun)
activity that tries to conceal something	the activity of keeping something secret
a covering to disguise or conceal the face
a protective covering worn over the face
a party of guests wearing costumes and masks

mask (adjective)	concealing (adjective)
	covering or hiding

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