G0878
ἄφρων
foolish
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)
Full Thayer's lexicon entry
ἄφρων — áphrōn
ἄφρων, ἀφρωνος, ὁ, ἡ, Ἄφρον, τό (from the alpha privative and φρήν, cf. εὔφρων, σώφρων) (from Homer down), properly, without reason ((εἴδωλα, Xenophon, mem. 1, 4, 4); of beasts, ibid. 1, 4, 14), senseless, foolish, stupid; without refection or intelligence, acting rashly: Luk 11:40; Luk 12:20; Rom 2:20; 1Co 15:36; 2Co 11:16; 2Co 11:19 (opposed to φρόνιμος, as in Pro 11:29); 2Co 12:6; 2Co 12:11; Eph 5:17 (opposed to συνιέντες); 1Pe 2:15. (A strong term; cf. Schmidt, chapter 147 § 17.)
10 occurrences
Luke (2), Romans (1), I Corinthians (1), II Corinthians (4), Ephesians (1), I Peter (1)