Jeremiah 6:27-30
I have set thee for a tower and a fortress among my people, that thou mayest know and try their way. They are all grievous revolters, walking with slanders: they are brass and iron; they are all corrupters. The bellows are burned, the lead is consumed of the fire; the founder melteth in vain: for the wicked are not plucked away. Reprobate silver shall men call them, because the LORD hath rejected them.

Romans 1:28
And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient;

2 Timothy 3:8
Now as Jannes and Jambres withstood Moses, so do these also resist the truth: men of corrupt minds, reprobate concerning the faith.

Titus 1:16
They profess that they know God; but in works they deny him, being abominable, and disobedient, and unto every good work reprobate.

When someone has tasted the good of YAHUSHUA and then turns around and worships satan or denies that YAHUSHUA is LORD and GOD, they are reprobate.

Hebrews 6:1-6
Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment. And this will we do, if God permit. For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, And have tasted the good word of God, and the powers of the world to come, If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.