remnant vs leftover

remnant and leftover both are nouns.

Word	Noun	Adjective	Verb	Adverb
remnant	Yes	No	No	No
leftover	Yes	Yes	No	No

As nouns, remnant and leftover are synonyms defined as:

remnant and leftover: a small part or portion that remains after the main part no longer exists

remnant (noun)	leftover (noun)
a piece of cloth that is left over after the rest has been used or sold	a small part or portion that remains after the main part no longer exists
a small part or portion that remains after the main part no longer exists

remnant (adjective)	leftover (adjective)
	not used up