General Synonyms:
* Poison (most common, often used interchangeably)
* Toxins (more scientific, refers to the specific substances)
* Virus (can be used in some contexts, but is technically a different type of pathogen)
* Toxin (refers to a specific poison produced by a living organism)
* Poisons (plural form of poison)
* Toxic substance (more formal and scientific)
Synonyms Emphasizing the Harm:
* Blight
* Bane
* Death (in extreme cases)
* Malice (when referring to emotional venom)
* Hate (similar to malice)
Synonyms Emphasizing the Source:
* Secretion (general term for any substance produced by a living organism)
* Venomous substance (more specific)
* Contagion (when referring to a contagious poison)
The best synonym depends on the specific situation and what aspect of "venom" you want to emphasize.