In the Septuagint, the Greek translation of the old testament and in the Greek new testament we find these instances:
Joshua 22:22 The LORD God of gods, the LORD God of gods, he knoweth, and Israel he shall know; if it be in rebellion, or if in transgression against the LORD, (save us not this day,)
2Chronicles 29:19 Moreover all the vessels, which king Ahaz in his reign did cast away in his transgression, have we prepared and sanctified, and, behold, they are before the altar of the LORD.
Jeremiah 2:19 Thine own wickedness shall correct thee, and thy backslidings shall reprove thee: know therefore and see that it is an evil thing and bitter, that thou hast forsaken the LORD thy God, and that my fear is not in thee, saith the Lord GOD of hosts.
Acts 21:21 And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs.
2Thessalonians 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
Apostasia
In Joshua 22:22 it means to be in rebellion
In 2Chronicles 29:19 it means to cast away
In Jeremiah 2:19 it means forsaken
In Acts 21:21 it means to forsake
In 2 Thessalonians 2:3 it means a departure
All meanings are a type of separation! To rebel is to separate oneself.
To cast away is to separate from self.
To be forsaken is to be separated.
To forsake is to separate.
To depart is a separation.
Apostasia is the word that separates the tares from the wheat and also separates the wise from the foolish virgins!