Abbott-Smith Manual Greek Lexicon
ἀμαθής (G261)
1 ** ἀμαθής , -ές ( μανθάνω ), [in Sm.: Ps 49:11 *;] unlearned , ignorant : II Pe 3:16 (on the rareness of this word, v. MM, VGT , s.v.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain