nocuous
Likely to injure
Nocuous means harmful or noxious.
The word is rare, appearing mainly in formal or technical contexts where its more common negation, innocuous, might prompt curiosity about the positive form.
Something nocuous causes injury or damage: The nocuous effects of the chemical were well documented.
Causing harm or damage
- perniciousGradually and subtly harmful
- banefulCausing serious harm
- maleficentCausing harm or evil
- injuriousCausing physical harm
detrimental · damaging · destructive · hurtful · baleful · malignant · adverse · ruinous
Capable of causing death
- venomousProducing injected toxins
- contaminatingMaking something impure
- pollutingIntroducing harmful contaminants
- septicInfected with bacteria
infectious · pathogenic · carcinogenic · mutagenic · teratogenic · biohazardous · chemical · environmental
Likely to cause injury
- perilousFraught with danger
- unsafeLikely to cause harm
- riskyInvolving possible harm
- treacherousDisloyal and dangerous
menacing · threatening · jeopardous · precarious · dire · ominous · foreboding · sinister
deleterious
Causing harm or damage
- perniciousGradually and subtly harmful
- banefulCausing serious harm
- maleficentCausing harm or evil
injurious · detrimental · damaging · destructive · hurtful · baleful · malignant · adverse · ruinous · unwholesome
poisonous
Capable of causing death
- venomousProducing injected toxins
- contaminatingMaking something impure
- pollutingIntroducing harmful contaminants
septic · infectious · pathogenic · carcinogenic · mutagenic · teratogenic · biohazardous · chemical · environmental · radiological
hazardous
Likely to cause injury
treacherous · menacing · threatening · jeopardous · precarious · dire · ominous · foreboding · sinister · alarming
lethal
Causing or capable of death
life-threatening · deathly · terminal · virulent · venomous · pestilent · pestiferous · malign · murderous · destroying
nocuousbeneficial
Producing good results
salutary · healthful · healthy · wholesome · salubrious