noun, masculine/ʒə n(ə) sɛ kwa/
a certain something, je ne sais quoi (intangible quality that makes something distinctive)
“Si tu l'as, tu l'as, Ella elle l'a / Ce je ne sais quoi / Que d'autres n'ont pas” — If you have it, you have it, Ella she has it. This I don't know what. That the others don't have.
Synonyms: Dieu sait quoi, on ne sait quoi
Literally, “I don't know what”.