DUFF

Jim from Suttons Bay asked about the word duff, the decayed matter on a forest floor -- specifically, whether it has any connection to the phrase, an old duffer. Though they share a similar spelling and may both be Scottish terms, there is no direct connection. For a small word, duff has had many meanings, as The Oxford English Dictionary attests.

• Soft or spongy matter covering the ground, esp. decaying vegetable matter (fallen leaves, etc.) covering a forest floor; leaf mould. [Possible Scottish variant of dough.]
• Coal in the form of small particles and dust.
• Something worthless or fake; counterfeit money; smuggled goods. [Back formation from duffer, a dishonest peddlar, possible variant for a Scottish word meaning an incompetent person.]
• A boiled or steamed sweet pudding, usually containing fruit, and made in a bag.
• The buttocks; the backside.
• To alter the appearance of (something for sale) in a deceptive or misleading way, esp. so as to make it appear new or of superior quality; to fake, forge, counterfeit.
• Representing the sound of a dull blow, thud, or drumbeat. Frequently reduplicated.
• Originally of money: fake, counterfeit; not genuine. More generally: worthless, useless, inadequate, poor.
• To perform (a shot) badly. Also in extended use: to make a mess of (something), to muff.
• With up: to become foggy or hazy.
• To beat (a person) up, to thrash.
• A variant of dough.
• Dull, flat; lacking in spirit or energy, listless; inactive. Also: slow-witted, stupid.
• Sad, melancholy, out of spirits.

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