Strong's G646 — ἀποστασία (noun)
apostasia (ap-os-tas-ee'-ah) n.
1. defection from truth (properly, the state)
2. "apostasy"
[feminine of the same as G647]
KJV: falling away, forsake 
Root(s): G647 
Hebrew root: ἀποστάσιον
Occurrences: 2