Superlative form of the adjective 'chuff'; most pleased, delighted, or puffed out (British slang).
Superlative of 'chuffed' (British slang for pleased) formed with '-iest' suffix, following standard English superlative formation rules.
The happiness scale in British slang goes from 'chuffed' to 'chuffier' to 'chuffiest'—it's one of the more whimsical ways English speakers express increasing levels of contentment.
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