One who knows good and evil
A person with the ability to distinguish between good and evil; by extension, an adult who is mature enough to understand the meaning of their actions.
("For God knows that on the day you eat of it your eyes will be opened, and you will be like God, knowing good and evil" — Genesis 3:5 (the serpent to Eve), and also: "Woe to the master who does not know, happy is the master who does not know, woe to the master who does not know between good and evil" — Sanhedrin 103a, and also: "Furthermore, a human being has understanding, whereas an animal has no understanding; and furthermore, a human being knows between good and evil, whereas an animal does not know between good and evil" — Midrash Tanchuma (Buber), Parashat Emor, סימן כא)
Translation
Expression (Hebrew)
יוֹדֵעַ טוֹב וְרַע
Definition (Hebrew)
בַּעַל יְכֹולֶת לְהַבְחִין בֵּין טוֹב לְרַע. בְּהַשְׁאָלָה :בּוֹגֵר דַּיּוֹ כְּדֵי לְהָבִין אֶת מַשְׁמָעוּת מַעֲשָׂיו.
("כִּי יֹדֵעַ אֱלֹהִים כִּי בְּיוֹם אֲכָלְכֶם מִמֶּנּוּ וְנִפְקְחוּ עֵינֵיכֶם וִהְיִיתֶם כֵּאלֹהִים יֹדְעֵי טוֹב וָרָע"- בְּרֵאשִׁית ג ה (הַנָּחָשׁ לְחַוָּה), וְכֵן:"בְּכַי לֵהּ לְמָר דְּלָא יָדַע, חַיְּכִי לְמַר דְּלָא יָדַע, וַי לֵהּ לְמָר דְּלָא יָדַע בֵּין טָב לְבִישׁ"- סַנְהֶדְרִין קג ע"א, וְכֵן:"וְעוֹד שֶׁיֵּשׁ בָּאָדָם דַּעַת, וּבִבְהֵמָה אֵין דַּעַת, וְעוֹד שֶׁהָאָדָם יוֹדֵעַ בֵּין טוֹב לְרַע, וְהַבְּהֵמָה אֵינָהּ יוֹדַעַת בֵּין טוֹב לְרַע"-מִדְרַשׁ תַּנְחוּמָא (בּוּבֶּר) פָּרָשַׁת אֱמֹר סִימָן כא)