Noun
cruelty [pl. cruelties]
severity [pl. severities] , {feelings & emotions}
harshness [pl. harshnesses]
unkindness [pl. unkindnesses]
acrimony [pl. acrimonies]
oppressiveness [pl. oppressivenesses]
rigidity [pl. rigidities]
mercilessness {feelings & emotions}
austerity [pl. austerities]
rigor {feelings & emotions}
remorselessness [pl. remorselessnesses]
flintiness [pl. flintinesses]
...