opioid

1. A substance that has effects similar to opium:Examples: "Mechoulam concluded that our bodies must produce their own cannabinoids — endogenous molecules that, like the native opioids and nicotinelike molecules our bodies also make, engage the cannabinoid receptors throughout the human body."

2. A substance that has effects similar to opium:Examples: "The number of young children in the US who have died from opioid overdoses has increased significantly, according to a new study on accidental poisonings of children 5 and younger."