2
persistent
2
rancorous(adjective, mean, harsh, cruel, vicious)
2
rigid(adjective, harsh, cruel, determined, fierce)
2
severe(adjective, mean, harsh, cruel, vicious)
2
unmitigable
2
unsatisfied(adjective, avid, greedy, wanting, rapacious)
2
vindictive(adjective, mean, harsh, cruel, determined)
1
revengeful(adjective, mean, harsh, cruel, vicious)
1
acquisitive
1
all-devouring
1
avaricious
1
avenging
1
barbarous(adjective, mean, severe, harsh, cruel)
1
bottomless
1
bound(adjective, harsh, cruel, determined, fierce)
1
bound and determined(expression, adjective, idiom, harsh, cruel)
1
brutal(adjective, mean, harsh, cruel, vicious)
1
bullheaded(adjective, determined, resolute, uncompromising, unshakeable)
1
callous(adjective, mean, severe, harsh, cruel)
1
compassionless(adjective, mean, severe, harsh, cruel)
11 years ago|2.3k views|share |citing 
APASmart Define. (2015). unappeasable thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/unappeasable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unappeasable thesaurus" https://smartdefine.org/unappeasable/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, unappeasable thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/unappeasable/thesaurus/synonyms>.
MLASmart Define. "unappeasable thesaurus" 14 April 2015. Web. 25 September 2026. <https://smartdefine.org/unappeasable/thesaurus/synonyms>