Strong's G3912 — παραφρονέω (verb)
paraphroneo (par-af-ron-eh'-o) v.
1. to misthink, i.e. be insane (silly)
[from G3844 and G5426]
KJV: as a fool 
Root(s): G3844, G5426 
Hebrew root: φρονέω
Occurrences: 1