deadly
highly infective
toxic
unpleasant
acerb
acerbate
acerbic
acid
acidic
acidulent
acidulous
acrid
acrimonious
acute
antagonistic
antipathetic
astringent
baleful
baneful
belligerent
biting
bitter
brutal
burning
catching
caustic
choleric
clashing
colliding
communicable
conflicting
contagious
corroding
corrosive
corrupting
corruptive
counterproductive
cutting
damaging
dangerous
death-bringing
deathful
deathly
deleterious
despiteful
destructive
detrimental
disadvantageous
disserviceable
distressing
double-edged
virulence
virulently
virus
implacable
inveterate
lethal
malignant
obscene
outspoken
rancorous
scathing
scurrilous
vehement
venomous
vile
vindictive
violent