impurity vs dross

impurity and dross both are nouns.

Word	Noun	Adjective	Verb	Adverb
impurity	Yes	No	No	No
dross	Yes	No	No	No

As nouns, impurity and dross are synonyms defined as:

impurity and dross: worthless or dangerous material that should be removed

impurity (noun)	dross (noun)
the condition of being impure	the scum formed by oxidation at the surface of molten metals
worthless or dangerous material that should be removed	worthless or dangerous material that should be removed