plum duff vs duff

plum duff and duff both are nouns.

Word	Noun	Adjective	Verb	Adverb
plum duff	Yes	No	No	No
duff	Yes	No	No	No

As nouns, plum duff and duff are synonyms defined as:

plum duff and duff: a stiff flour pudding steamed or boiled usually and containing e.g. currants and raisins and citron

plum duff (noun)	duff (noun)
a stiff flour pudding steamed or boiled usually and containing e.g. currants and raisins and citron	a stiff flour pudding steamed or boiled usually and containing e.g. currants and raisins and citron