harmful (adj.)
- adverse
- antagonistic
- bad
- baleful
- baneful
- bitchy
- conflicting
- contaminated
- contrary
- corrosive
- corrupting
- corruptive
- counter
- counteractive
- counterproductive
- cussed
- damaging
- dangerous
- deadly
- deleterious
- destructive
- detrimental
- difficult
- disadvantageous
- distressing
- evil
- foul
- hard
- hateful
- hazardous
- hostile
- hurtful
- ill
- inimical
- iniquitous
- injurious
- insalubrious
- insanitary
- invidious
- lethal
- malefic
- maleficent
- malevolent
- malicious
- malign
- malignant
- mean
- mischievous
- miserable
- morbific
- nasty
- noisome
- noxious
- ominous
- opposed
- opposing
- opposite
- ornery
- pathogenic
- peccant
- pernicious
- pestiferous
- poisonous
- polluted
- prejudicial
- rigorous
- risky
- septic
- sinister
- stressful
- tainted
- toxic
- troublesome
- troublous
- trying
- unfavorable
- unhealthful
- unhealthy
- unhygienic
- unprofitable
- unrewarding
- unsafe
- unsanitary
- untoward
- unwholesome
- useless
- venomous
- vicious
- virulent
- wicked
- worthless
- wretched
