dross vs impurity

dross and impurity both are nouns.

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

As nouns, dross and impurity are synonyms defined as:

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

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