Strong's G5351 — φθείρω (verb)
phtheiro (fthei'-ro) v.
1. (properly) to shrivel or wither, i.e. to spoil (by any process)
2. (generally) to ruin
3. (especially figuratively, by moral influences) to deprave
[probably strengthened from phthio "to pine or waste"]
KJV: corrupt (self), defile, destroy 
Occurrences: 9