lassitude vs torpidity

lassitude and torpidity both are nouns.

Word	Noun	Adjective	Verb	Adverb
lassitude	Yes	No	No	No
torpidity	Yes	No	No	No

As nouns, torpidity is a hypernym of lassitude; that is, torpidity is a word with a broader meaning than lassitude:

lassitude: a state of comatose torpor (as found in sleeping sickness)
torpidity: a state of motor and mental inactivity with a partial suspension of sensibility

Other hypernyms of lassitude include torpor.

lassitude (noun)	torpidity (noun)
weakness characterized by a lack of vitality or energy	inactivity resulting from lethargy and lack of vigor or energy
a feeling of lack of interest or energy	a state of motor and mental inactivity with a partial suspension of sensibility
a state of comatose torpor (as found in sleeping sickness)