false god, foreign god, god, goddess

Definition:

A false god is something that people worship instead of the one true God. The term "goddess" refers specifically to a female false god.

These false gods or goddesses do not exist. Yahweh is the only God.
People sometimes make objects into idols to worship as symbols of their false gods.
In the Bible, God's people frequently turned away from obeying him in order to worship false gods.
Demons often deceive people into believing that the false gods and idols they worship have power.
Baal, Dagon, and Molech were three of the many false gods that were worshiped by people in Bible times.
Asherah and Artemis (Diana) were two of the goddesses that ancient peoples worshiped.

There may already be a word for "god" or "false god" in the language or in a nearby language.
The term "idol" could be used to refer to false gods.
In English, a lower case "g" is used to refer to false gods, and upper case "G" is used to refer to the one true God. Other languages also do that.
Another option would be to use a completely different word to refer to the false gods.
Some languages may add a word to specify whether the false god is described as male or female.

10-02 Through these plagues, God showed Pharaoh that he is more powerful than Pharaoh and all of Egypt's gods.
13-04 Then God gave them the covenant and said, "I am Yahweh, your God, who saved you from slavery in Egypt. Do not worship other gods."
14-02 They (Canaanites) worshiped false gods and did many evil things.
16-01 The Israelites began to worship the Canaanite gods instead of Yahweh, the true God.
18-13 But most of Judah's kings were evil, corrupt, and they worshiped idols. Some of the kings even sacrificed their children to false gods.