Where is this written?
Figuratively: Since when is this accepted or customary? Or: There is no basis for this. It is not accepted.
(Modern Hebrew)
Translation
Expression (Hebrew)
אֵיפָה זֶה כָּתוּב?
Definition (Hebrew)
בְּהַשְׁאָלָה: מִמָּתַי זֶה מְקֻבָּל אוֹ נָהוּג? אוֹ: אֵין לְכָךְ אַסְמַכְתָּא. זֶה לֹא מְקֻבָּל.
(הָעִבְרִית הַחֲדָשָׁה)