je ne sais quoi /ʒənəˌseɪˈkwɑː/ noun Learner's definition of JE NE SAIS QUOI
[singular] sometimes humorous
: a pleasant quality that is hard to describe难以描述的好品质;妙不可言的特性 ◊ In French the phrase je ne sais quoi means literally “I know not what.”*je ne sais quoi为法语短语,字面意思是I know not what。