he cursed endlessly, unravelling with no less depravity - (13)

I believe the answer is:

lecherousness

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'depravity' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'he cursed endlessly unravelling with no less' is the wordplay.
'endlessly' means to remove the last letter.
'unravelling with' indicates an anagram.
'he'+'cursed'='hecursed'
'hecursed' with its last letter taken away is 'hecurse'.
'no'+'less'='noless'
'hecurse' anagrammed with 'noless' can make 'LECHEROUSNESS'.

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