lassitude vs languor

lassitude and languor both are nouns.

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

As nouns, lassitude and languor are synonyms defined as:

Other synonyms of lassitude include listlessness.

lassitude (noun)	languor (noun)
weakness characterized by a lack of vitality or energy	inactivity; showing an unusual lack of energy
a feeling of lack of interest or energy	a relaxed comfortable feeling
a state of comatose torpor (as found in sleeping sickness)	a feeling of lack of interest or energy
	oppressively still air