He doesn't have a green clue
(Slang) Lacking any minimal knowledge. He doesn't know a thing.
(Modern Hebrew)
Translation
Expression (Hebrew)
אֵין לוֹ מֻשָּׂג יָרֹק
Definition (Hebrew)
חָסֵר כָּל יֶדַע מִינִימָלִי. אֵינֶנּוּ יוֹדֵעַ דָּבָר.
(הָעִבְרִית הַחֲדָשָׁה)