Here is the Biblical definition:
Deuteronomy 13:1 “If a prophet or someone who has dreams arises among you and proclaims a sign or wonder to you, 2 and that sign or wonder he has promised you comes about, but he says, ‘Let us follow other gods,’ which you have not known, ‘and let us worship them,’ 3 do not listen to that prophet’s words or to that dreamer. For the Lord your God is testing you to know whether you love the Lord your God with all your heart and all your soul. 4 You must follow the Lord your God and fear Him. You must keep His commands and listen to His voice; you must worship Him and remain faithful to Him. 5 That prophet or dreamer must be put to death, because he has urged rebellion against the Lord your God who brought you out of the land of Egypt and redeemed you from the place of slavery, to turn you from the way the Lord your God has commanded you to walk. You must purge the evil from you.
Following other gods like keeping Christmas with all the pagan idols and symbols or Easter with all those pagan idols and symbols.
6 “If your brother, the son of your mother, or your son or daughter, or the wife you embrace, or your closest friend secretly entices you, saying, ‘Let us go and worship other gods’—which neither you nor your fathers have known, 7 any of the gods of the peoples around you, near you or far from you, from one end of the earth to the other— 8 you must not yield to him or listen to him. Show him no pity, and do not spare him or shield him. 9 Instead, you must kill him. Your hand is to be the first against him to put him to death, and then the hands of all the people. 10 Stone him to death for trying to turn you away from the Lord your God who brought you out of the land of Egypt, out of the place of slavery. 11 All Israel will hear and be afraid, and they will no longer do anything evil like this among you.
For example the New Age movement.
There is also this
Deuteronomy 18:20 But the prophet who presumes to speak a word in my name that I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die.’ 21 And if you say in your heart, ‘How may we know the word that the Lord has not spoken?’— 22 when a prophet speaks in the name of the Lord, if the word does not come to pass or come true, that is a word that the Lord has not spoken; the prophet has spoken it presumptuously. You need not be afraid of him.
This does not refer to someone interpreting scripture incorrectly like Apollos. You have to say that the Lord gave you this word, this would refer to the Mormon's and the book of Mormon.
Before you decide to stone someone better makes sure you understand the law.