Present participle: the process of making something badly or dishonestly.
From 'fudge' plus the progressive suffix '-ing', which creates the continuous form and can function as gerund or adjective.
British speakers often use 'fudging' as a euphemistic intensifier ('That's fudging brilliant!'), where it replaces a much stronger word—a perfect example of how swearing and emphasis work in different English dialects.
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