retentivity vs impermeability

retentivity and impermeability both are nouns.

Word	Noun	Adjective	Verb	Adverb
retentivity	Yes	No	No	No
impermeability	Yes	No	No	No

As nouns, impermeability is a hypernym of retentivity; that is, impermeability is a word with a broader meaning than retentivity:

retentivity: the power of retaining liquid
impermeability: the property of something that cannot be pervaded by a liquid

Other hypernyms of retentivity include impermeableness.

retentivity (noun)	impermeability (noun)
the power of retaining liquid	the property of something that cannot be pervaded by a liquid
the property of retaining possessions that have been acquired
the power of retaining and recalling past experience