japery vs craziness

japery and craziness both are nouns.

Word	Noun	Adjective	Verb	Adverb
japery	Yes	No	No	No
craziness	Yes	No	No	No

As nouns, craziness is a hypernym of japery; that is, craziness is a word with a broader meaning than japery:

Other hypernyms of japery include folly, foolery, indulgence, lunacy, tomfoolery.

japery (noun)	craziness (noun)
acting like a clown or buffoon	foolish or senseless behavior
	the quality of being rash and foolish
	informal terms for insanity