deadly
Definitions
Causing or able to cause death.
Extremely intense, persistent, or boring.
Relentless or implacable in nature.
Examples
The cobra is known for its deadly venom.
A deadly storm swept through the coastal town last night.
He made a deadly mistake by ignoring the safety warnings.
Synonyms
lethal fatal mortal terminal virulent destructive pernicious
Antonyms
harmless safe beneficial salutary wholesome innocuous nontoxic