Most prone to quick, restless movements; most fidgety or energetic.
From 'fliskier' with superlative '-est' (Old English 'ost'), which marks the extreme degree of an adjective.
The '-est' superlative suffix has been marking the ultimate degree in English for over 1,500 years—it's one of the oldest grammatical patterns we still use regularly, showing how stable the core grammar of a language can be.
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