joke vs slightness

joke and slightness both are nouns.

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

As nouns, slightness is a hypernym of joke; that is, slightness is a word with a broader meaning than joke:

Other hypernyms of joke include pettiness, puniness, triviality.

joke (noun)	slightness (noun)
a ludicrous or grotesque act done for fun and amusement	slenderness
activity characterized by good humor	the property of an attractively thin person
a triviality not to be taken seriously	the quality of being unimportant and petty or frivolous
a humorous anecdote or remark intended to provoke laughter

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