The term 'false teacher' can be thrown around the body of Christ just because you disagree with them.
Just because you disagree with them theologically doesn't mean you still can't love biblically.
You'll see that there are believers who truly love the Lord, but have been raised in a denomination that teaches doctrine that doesn't align with the word of God versus somebody who's wicked, prideful & doesn't like correction.
And the Lord said to me, “The prophets prophesy lies in My name. I have not sent them, commanded them, nor spoken to them; they prophesy to you a false vision, divination, a worthless thing, and the deceit of their heart. (Jeremiah 14:14)
Signs of a false teacher...
#1 Do they lift themselves up after they talk or teach... or do they lift up the name of Jesus
Who is receiving the glory?
Just like the Pharisees honor with their lips but heart is far from the Lord.
7 If you abide in Me, and My words abide in you, you will ask what you desire, and it shall be done for you. 8 By this My Father is glorified, that you bear much fruit; so you will be My disciples. (John 15:7-8)
#2 They teach on what sounds good, instead of what needs to be said
If none of the messages or teachings you hear or conversations you have convict you, it may not be sound doctrine.
3 For the time will come when they will not endure sound doctrine, but according to their own desires, because they have itching ears, they will heap up for themselves teachers; (2 Timothy 4:3)
#3 They fear people over God
24 Then Saul said to Samuel, “I have sinned, for I have transgressed the commandment of the LORD and your words, because I feared the people and obeyed their voice. (1 Samuel 15:24)
This is Saul on why he disobeyed God because he feared man's opinion.
He feared man's opinion and the people over God's instructions & God's commandments.
If you fear people more than you fear God then it's going to be hard to fulfill a ministry that is ordained and led by God.
#4 Reach for their opinions or the word of God (Acts 17)
Is what they speak about backed up by their own opinion or scripture?
Where do they get the revelation from?
I always try to back up any questions I get with scripture so they can go back and search the scriptures themselves.
10 Then the brethren immediately sent Paul and Silas away by night to Berea. When they arrived, they went into the synagogue of the Jews. 11 These were more fair-minded than those in Thessalonica, in that they received the word with all readiness, and searched the Scriptures daily to find out whether these things were so. (Acts 17:10)
They received the word and then searched the scriptures daily themselves.
#5 Prayer life
You'll know somebody by their prayer life and how they pray.
They may not know that much scripture but their prayers are pure.
4 Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons, 2 speaking lies in hypocrisy, having their own conscience seared with a hot iron, 3 forbidding to marry, and commanding to abstain from foods which God created to be received with thanksgiving by those who believe and know the truth. 4 For every creature of God is good, and nothing is to be refused if it is received with thanksgiving; 5 for it is sanctified by the word of God and prayer. (1 Timothy 1-5)
The powerful thing about God's word and prayer is that it allows us to be separated and sanctified from these doctrines of deception, seducing spirits that speak lies and hypocrisy.