Definition of joke
1a : something said or done to provoke laughter especially : a brief oral narrative with a climactic humorous twist
b(1) : the humorous or ridiculous element in something
(2) : an instance of jesting : kidding can’t take a joke
c : practical joke
d : laughingstock
2 : something not to be taken seriously : a trifling matter consider his skiing a joke —Harold Callender —often used in negative constructions it is no joke to be lost in the desert
(Source: Merriam-Webster)