malignant (adj.)

• acrid
• allergic
• anemic
• antagonistic
• antipathetic
• apoplectic
• arthritic
• atrocious
• baleful
• baneful
• barbaric
• barbarous
• belligerent
• bestial
• bilious
• bitchy
• bitter
• bloody
• brutal
• brutish
• cancerous
• catching
• caustic
• chlorotic
• clashing
• colicky
• communicable
• conflicting
• consumptive
• contagious
• corrosive
• corrupting
• corruptive
• counterproductive
• cussed
• damaging
• deadly
• deathly
• deleterious
• despiteful
• destructive
• detrimental
• devilish
• diabolical
• disadvantageous
• distressing
• dropsical
• dyspeptic
• edematous
• epileptic
• evil
• fatal
• feral
• ferine
• ferocious
• fiendish
• fierce
• harmful
• hateful
• hostile
• hurtful
• infectious
• infective
• inhuman
• iniquitous
• injurious
• internecine
• invidious
• killing
• leprous
• lethal
• malarial
• malefic
• maleficent
• malevolent
• malicious
• malign
• mean
• measly
• mephitic
• merciless
• miasmal
• miasmic
• mischievous
• mortal
• murderous
• nasty
• nephritic
• neuralgic
• noisome
• noncivilized
• noxious
• ominous
• ornery
• palsied
• paralytic
• pernicious
• pestiferous
• pestilential
• pitiless
• pneumonic
• poisonous
• prejudicial
• quarrelsome
• rachitic
• rancorous
• repugnant
• rheumatic
• rickety
• ruthless
• sanguinary
• savage
• scorbutic
• scrofulous
• sore
• spiteful
• toxic
• toxicant
• tubercular
• tuberculous
• uncivilized
• ungentle
• untamed
• venomous
• vicious
• virulent
• vitriolic
• wicked
• wild