British slang meaning exhausted, tired, or worn out.
From the verb 'fag' (to tire or exhaust), which derives from Middle English 'faggen.' In British schools, 'fagging' referred to younger students doing chores for older ones, which was exhausting work.
The word 'fagged' is completely innocent in British English (just meaning tired), but it's taboo in American English due to a homonym slur, showing how the same word can have totally different social meanings across dialect boundaries.
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