Definition of "Sucker" :

noun: mostly North American freshwater fishes with a thick-lipped mouth for feeding by suction; related to carps

noun: an organ specialized for sucking nourishment or for adhering to objects by suction

noun: hard candy on a stick

noun: flesh of any of numerous North American food fishes with toothless jaws

noun: a person who is gullible and easy to take advantage of

noun: a drinker who sucks (as at a nipple or through a straw)

noun: a shoot arising from a plant's roots