A substance that is harmful or lethal to a living organism when ingested. / Something that harms a person or thing.

(transitive) To use poison to kill or paralyse (somebody). / (transitive) To pollute; to cause to become poisonous. / (transitive) To cause to become much worse.

plural of blood poisoning

Any of the poisonous frogs of the family Dendrobatidae.

Containing sufficient poison to be dangerous to touch or ingest. / (figuratively) Negative, harmful.

A person who poisons something or someone.

In a poisonous manner. / (obsolete) Using poison.

plural of poisoner

A potentially fatal medical condition, also called water intoxication, caused by extremely rapid intake of water. / Contaminating a water source with a toxin.

Any of three ivy-like species of Toxicodendron, known for their ability to cause an itching rash and blistering for most people, through urushiol, an oil that is a skin irritant.