Je ne sais quoi is a phrase, borrowed from French, literally meaning I don’t know what.
It is generally used as a sophisticated way of alluding to the inexplicable good or bad traits of people.
The expression was adopted into English from French during the 1600’s, when French was still the language of choice for aristocracy, as well as diplomacy and trade.
Throughout the centuries, “je ne sais quoi” grew to be a part of the English lexicon, applied by many to give the impression of sophistication.
“Je ne sais quoi” was first defined on Urban Dictionary in 2004.
The expression served as the title of several songs, Icelandic singer Hera Björk performed one such track on the 2010 Eurovision Contest.