resentful
acerb
acerbate
acerbic
acid
acidic
acidulent
acidulous
acrid
acrimonious
antagonistic
antipathetic
avenging
belligerent
bitter
burning
caustic
choleric
clashing
colliding
conflicting
despiteful
embittered
envenomed
evil
full of hate
grudgeful
hateful
hostile
implacable
irreconcilable
malevolent
malicious
malign
malignant
punitive
punitory
quarrelsome
rankled
repugnant
resenting
retaliatory
revanchist
revengeful
set against
sore
deep-seated
envious
factional
ill-concealed
ineradicable
internecine
inveterate
long-standing
sectarian
sectional
spiteful
unforgiving
ungovernable
unreasoning
vindictive
virulent
cantankerous