poisonous
Containing a substance that causes illness or death if ingested or absorbed.
Adjective
This term specifically describes a passive danger. A poisonous organism is one that is harmful to eat or touch, acting as a chemical defense mechanism. It describes a state of being toxic rather than an active delivery of toxins.
In a social or psychological sense, it describes an atmosphere or relationship that is destructive and corrosive. A poisonous environment slowly drains the morale or mental health of those within it, mirroring the way a toxin slowly degrades a biological system.