6
mortally(adverb, fatally)
5
fatally(adverb, fatally)
4
fatefully
4
terminally(adverb, fatally)
3
deadly
3
deathly
3
fatal
3
incurably
3
lethal
3
murderously
3
perniciously
3
pestilently
2
banefully
2
destructively
2
homicidally
2
incurable
2
killingly
2
virulently
1
atrocious
1
badly
13 years ago|1.3k views|share |citing 
APASmart Define. (2013). lethally thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/lethally/thesaurus/synonyms
ChicagoSmart Define. 2013. "lethally thesaurus" https://smartdefine.org/lethally/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2013, lethally thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/lethally/thesaurus/synonyms>.
MLASmart Define. "lethally thesaurus" 17 June 2013. Web. 20 September 2026. <https://smartdefine.org/lethally/thesaurus/synonyms>