The quality or state of being fatuitous; extreme foolishness and senselessness combined with self-satisfied confidence.
From 'fatuitous' (adjective) plus the noun-forming suffix '-ness', abstracting the characteristic quality of being absurdly foolish.
The '-ness' suffix transforms almost any adjective into an abstract noun exploring 'the quality of being that way'—this creates some wonderfully unwieldy words like 'fatuitousness' that sound almost as foolish as what they describe.
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