lassitude vs listlessness

lassitude and listlessness both are nouns.

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

As nouns, lassitude and listlessness are synonyms defined as:

Other synonyms of lassitude include languor.

lassitude (noun)	listlessness (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 feeling of lack of interest or energy
a state of comatose torpor (as found in sleeping sickness)