Listlessness even now needs upgrading into headings (5)

I believe the answer is:

ennui

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'listlessness' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for ennui that I've seen before include "Boredom, tedium" , "Weariness with life" , "Lack of interest" , "Boredom, listlessness" , "bore" .)

I've seen this clue in the Sydney Morning Herald.

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