Foolish, silly, or insipid; lacking sense or substance (archaic Latin-based term rarely used in modern English).
Direct from Latin 'fatuus' meaning foolish or insipid; the root is unclear but may be connected to 'fames' (hunger/emptiness), suggesting something empty-headed.
In medieval and Renaissance Europe, 'fatuus' appeared in Latin philosophical texts to describe spiritual or intellectual emptiness, making it a learned insult in the most educated circles.
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