joke vs joker

joke and joker both are nouns.

Word	Noun	Adjective	Verb	Adverb
joke	Yes	No	Yes	No
joker	Yes	No	No	No

joke (noun)	joker (noun)
a ludicrous or grotesque act done for fun and amusement	a playing card that is usually printed with a picture of a jester
activity characterized by good humor	an inconspicuous clause in a document or bill that affects its meaning in a way that is not immediately apparent
a triviality not to be taken seriously	a person who enjoys telling or playing jokes
a humorous anecdote or remark intended to provoke laughter	a person who does something thoughtless or annoying

joke (verb)	joker (verb)
act in a funny or teasing way
tell a joke; speak humorously