Languor (9)
'languor' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for lassitude that I've seen before include "Listlessness, lethargy" , "Weakness" , "30 [LETHARGY]" , "Is saluted with tiredness" , "slackness" .)
'languor' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ennui that I've seen before include "World-weariness" , "Result of boredom" , "having nothing to do" , "Low interest rate" , "French boredom and lassitude" .)