Probably form the base of G3466; dull or stupid (as if shut {up}) that {is} {heedless} (morally) {blockhead} (apparently) absurd: - fool ({-ish} X -ishness).
Verse
Matrix
Eph 5:4Neither filthiness, nor foolish talkingG3473, nor jesting, which are not convenient: but rather giving of thanks.