Defining a false prophet:
The scriptures say that they will appear Christian (Mat 7:15) and that they will even be convinced that they are Christian (Mat 7:22).
They will be successful, introducing heresy into the church. These heresies will be destructive even to the point of denying the Lord (2 Pet 2:1)
Many will follow them, as they spread heresy (2 Pet 2:2) they are greedy, and will make up lies to try and convince you that they are correct. (2 Pet 2:3).
As Christians we are to test these spirits whether they are of God, because there are many of them (1 John 4:1)
They will be convincing, because they will perform great wonders and even Christians will be mislead (Mat 24:24, Mark 13:22, Rev 13:13, Rev 13:14, Rev 19:20).
People will defend the false prophet because of their own desires (2 Tim 4:3)
These people will believe falsehood over truth (2 Tim 4:4)
When the day of judgement comes they will be rejected by God (Mat 7:21, Mat 7:23) because of their wickedness.
So, this is what a false prophet is, and the scriptures tell us that they are around. So next time when someone’s prophecy does not come to pass, are we to forgive them, and keep our fellowship with them intact.
When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him (Deuteronomy 18:22).