fatal
baleful
baneful
brutal
corroding
corrosive
corrupting
corruptive
counterproductive
damaging
deadly
death-bringing
deathful
deathly
deleterious
destructive
detrimental
disadvantageous
disserviceable
distressing
feral
harmful
hurtful
injurious
internecine
killing
malefic
malevolent
malign
malignant
mischievous
mortal
noisome
noxious
ominous
pernicious
pestilent
pestilential
poisonous
prejudicial
savage
scatheful
toxic
venenate
veneniferous
venenous
venomous
lethality
semilethal
devastate
formidable
hazardous
magical
murderous
serious
vicious
nonlethal