"Duff" was originally an alternative pronunciation of "dough" (cf "enough").
So it also came to mean a kind of pudding, "plum duff". And hence you could be "up the duff" if you were pregnant, just as you might "have a bun in the oven".
From the sense of "dough" it also came to mean flour, and then to chaff, or useless stuff. Hence "duff" meaning useless or broken.
So it also came to mean a kind of pudding, "plum duff". And hence you could be "up the duff" if you were pregnant, just as you might "have a bun in the oven".
From the sense of "dough" it also came to mean flour, and then to chaff, or useless stuff. Hence "duff" meaning useless or broken.