duff
UK[dʌf]US[dʌf]
n
A boiled or steamed pudding, often containing dried fruit
adj
Of poor quality; worthless or useless
v
To make something look new or different in order to deceive; to fake or alter something fraudulently
Etymology
The word 'duff' originated in the 19th century as a northern English dialectal pronunciation and spelling alteration of the word 'dough'. This phonological shift is a common feature of regional speech. The term was first applied to a type of pudding made from dough, typically boiled or steamed with fruit, which became a traditional dish. From this concrete culinary sense, the word's meaning broadened metaphorically; by the mid-19th century, 'duff' had acquired the informal adjectival sense of something being of poor quality or useless, likely influenced by the pudding's plain or heavy nature. The verbal sense, meaning to fake or alter fraudulently, emerged in American slang in the 20th century, extending the concept of worthlessness into the realm of deception.
Analysis
The word 'duff' is a simplex word. It is a British dialectal alteration of the word 'dough'. Its functional role is as a complete lexical root.
Examples
For dessert, we had a rich plum duff with custard.
His advice was completely duff and didn't help us at all.
The criminals attempted to duff up the serial numbers on the stolen goods.