Simple past tense and past participle of duff.(verb)
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Use "duffed" in a sentence
"The German quickly won back two holes with birdies and was given a third when his opponent inexplicably duffed his approach shot at the 9th from the middle of the fairway."
"But in commercial terms, has Chubby duffed his chance of maximising the big payday?"
"If you remove from the calculation the aberrant Quevega, who once more duffed up inferior rivals in the Mares' Hurdle, the average comes down to 45."