dupe vs sucker

dupe and sucker both are nouns.

Word	Noun	Adjective	Verb	Adverb
dupe	Yes	No	Yes	No
sucker	Yes	No	No	No

As nouns, sucker is a hyponym of dupe; that is, sucker is a word with a more specific, narrower meaning than dupe:

dupe (noun)	sucker (noun)
a person who is tricked or swindled	mostly North American freshwater fishes with a thick-lipped mouth for feeding by suction; related to carps
	an organ specialized for sucking nourishment or for adhering to objects by suction
	hard candy on a stick
	flesh of any of numerous North American food fishes with toothless jaws
	a drinker who sucks (as at a nipple or through a straw)
	a person who is gullible and easy to take advantage of
	a shoot arising from a plant's roots

dupe (verb)	sucker (verb)
fool or hoax