mischief vs mischievousness

mischief and mischievousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
mischief	Yes	No	No	No
mischievousness	Yes	No	No	No

As nouns, mischief and mischievousness are synonyms defined as:

mischief and mischievousness: reckless or malicious behavior that causes discomfort or annoyance in others

Other synonyms of mischief include devilment, devilry, deviltry, mischief-making, rascality, roguery, roguishness, shenanigan.

mischief (noun)	mischievousness (noun)
reckless or malicious behavior that causes discomfort or annoyance in others	reckless or malicious behavior that causes discomfort or annoyance in others
the quality or nature of being harmful or evil	an attribute of mischievous children
	the trait of behaving like an imp