ματαιόω G3154
mataióō · mat-ah-yo'-o · Verb
from μάταιος; to render (passively, become) foolish, i.e. (morally) wicked or (specially), idolatrous:--become vain.
1 Occurrence in the King James Bible
Romans 1:21Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.