The difference between Rube and Sucker

Rube as a noun (US, Canada, informal):

A person of rural heritage; a yokel.

Rube as a noun (pejorative):

An uninformed, unsophisticated, or unintelligent person.

Sucker as a noun:

A person or animal that sucks, especially a breast or udder; especially a suckling animal, young mammal before it is weaned.

Sucker as a noun (horticulture):

An undesired stem growing out of the roots or lower trunk of a shrub or tree, especially from the rootstock of a grafted plant or tree.

Sucker as a noun:

A parasite; a sponger.

Sucker as a noun:

An organ or body part that does the sucking; especially a round structure on the bodies of some insects, frogs, and octopuses that allows them to stick to surfaces.

Sucker as a noun:

A thing that works by sucking something.

Sucker as a noun:

The embolus, or bucket, of a pump; also, the valve of a pump basket.

Sucker as a noun:

A pipe through which anything is drawn.

Sucker as a noun:

A small piece of leather, usually round, having a string attached to the center, which, when saturated with water and pressed upon a stone or other body having a smooth surface, adheres, by reason of the atmospheric pressure, with such force as to enable a considerable weight to be thus lifted by the string; formerly used by children as a plaything.

Sucker as a noun (British, colloquial):

A suction cup.

Sucker as a noun:

An animal such as the octopus and remora, which adhere to other bodies with such organs.

Sucker as a noun:

Any fish in the family Catostomidae of North America and eastern Asia, which have mouths modified into downward-pointing, suckerlike structures for feeding in bottom sediments

Sucker as a noun (American, informal):

A piece of candy which is sucked ; a lollipop

Sucker as a noun (slang, archaic):

A hard drinker; a soaker.

Sucker as a noun (American, obsolete):

An inhabitant of Illinois.

Sucker as a noun (American, slang):

A person who is easily deceived, tricked or persuaded to do something; a naive person

Sucker as a noun:

A person irresistibly attracted by something specified.

Sucker as a noun (obsolete, vulgar, British slang):

The penis.

Sucker as a verb (horticulture, transitive):

To strip the suckers or shoots from; to deprive of suckers.

Sucker as a verb (horticulture, intransitive):

To produce suckers, to throw up additional stems or shoots.

Sucker as a verb (transitive):

To fool someone; to take advantage of someone.

Sucker as a noun (slang):

A thing or object. Any thing or object being called attention to with emphasis, as in "this sucker".

Sucker as a noun (informal):

Generalized term of reference to a person.