What does opiate agonists mean?

Opiate agonists.: Opiate agonists are medications that stimulate opioid receptors and therefore produce at least some opioid sensation. There are hundreds of opiate receptor agonists. They are sometimes known as mu receptor agonists.

"opium-like" : It is a substance which has "positive" activity on the opioid receptor. Examples would be morphine, codeine, heroin, and fentanyl. The opposite would be an antagonist, such as Naloxone (narcan).

Agonist definition: That means drugs that bind to and activate one of the opiate receptors on the surface of cells. There are a number of different opiate receptors. The "mu" receptor is the one responsible for pain relief. Opiate "antagoniosts" are drugs that bind to the opiate receptors without activating them and prevent agonists from binding to the receptors.

Means: these medications bind to opiate receptors in the body and depending on what receptors can cause different effects.