The process or state of being tired or exhausted; weariness caused by labor or exertion.
From Latin 'fatigatio' (weariness), derived from 'fatigare' (to tire) + '-tion' suffix. An extremely rare scholarly noun from the scholarly Latin tradition, barely attested in English.
This word is so obscure that most dictionaries don't even list it! But materials scientists still use 'fatigation' as a technical term for the microscopic damage metals suffer under repeated stress—it's literally the 'tiring out' of the metal itself.
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