Strong's G3154 — ματαιόω (verb)
mataioo (mat-ai-oh'-o) v.
1. to render (passively, become) foolish
2. (morally) wicked
3. (specially) idolatrous
[from G3152]
KJV: become vain 
Root(s): G3152 
Hebrew root: μάταιος
Occurrences: 1