The quality of being somewhat silly, foolish, or prone to doting behavior.
From 'dotish' (adjective) + '-ness' (noun suffix). Follows standard English pattern for creating abstract nouns from adjectives.
Notice how English lets us be really specific about levels of foolishness—'silliness,' 'dottiness,' and 'dotishness' are all slightly different shades of the same basic idea.
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