The quality or state of being dusk; the characteristic darkness and dim light of twilight; an alternative form to 'duskiness.'
From 'dusk' plus the noun-forming suffix '-ness' (directly, without the intermediate '-y' of 'duskiness'). Both 'duskness' and 'duskiness' existed as variant forms.
The existence of both 'duskness' and 'duskiness' shows the flexibility of English noun formation—different speakers and writers chose different paths, and only one form eventually became standard.
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