Luke 11:40ἄφρονες
You fools! Did not the One who made the outside make the inside as well?
Romans 2:20ἀφρόνων
an instructor of the foolish, a teacher of infants, because you have in the law the embodiment of knowledge and truth—
1 Corinthians 15:36ἄφρων
You fool! What you sow does not come to life unless it dies.
2 Corinthians 11:16ἄφρονα
I repeat: Let no one take me for a fool. But if you do, then receive me as a fool, so that I too may boast a little.
Ephesians 5:17ἄφρονες
Therefore do not be foolish, but understand what the Lord’s will is.
1 Peter 2:15ἀφρόνων
For it is God’s will that by doing good you should silence the ignorance of foolish men.

Abbott-Smith

ἄφρων, -ον genitive -ονος
(φρήν), [in LXX for כְּסִיל, נָבָל, etc. ;]
without reason, senseless, foolish, expressing "want of mental sanity and sobriety, a reckless and inconsiderate habit of mind" (Hort; cf. MM, see word): Luk.11:40 12:20, Rom.2:20, 1Co.15:36, 2Co.11:16 12:6 12:11, 1Pe.2:15; opposite to φρόνιμος, 2Co.11:19; to συνιέντες, Eph.2:17.†
(AS)

Sources: Abbott-Smith’s Manual Greek Lexicon of the New Testament (1922, public domain) and glosses from STEPBible TBESG (CC BY 4.0); STEPBible TAGNT (Greek New Testament, CC BY 4.0); the Berean Standard Bible (public domain). Reformatted by Word Study, wording unchanged. All sources and licenses.