secretiveness vs mum

secretiveness and mum both are nouns.

Word	Noun	Adjective	Verb	Adverb
secretiveness	Yes	No	No	No
mum	Yes	Yes	No	No

As nouns, mum is a hyponym of secretiveness; that is, mum is a word with a more specific, narrower meaning than secretiveness:

Other hyponyms of secretiveness include enigmaticness.

secretiveness (noun)	mum (noun)
characterized by a lack of openness (especially about one's actions or purposes)	secrecy
the trait of keeping things secret	informal terms for a mother
	of China

secretiveness (adjective)	mum (adjective)
	failing to speak or communicate etc when expected to