je ne se quoi
オーストラリアオープン決勝の模様を,BBC newsがTwitterで伝えています。je ne se quoiは「言葉では言い表せないもの」という意味で,フランス語je ne sais quoi(I don’t know what)が由来です(Weblio 辞典)。発音は/ˌʒə nə sɛ ˈkwɑː/。インターネットで検索してみると、have a certain je ne se quoiという形で使われることが多いようです。(Sugiuchi)
Just a 10-minute break to close the roof, which adds a certain je ne se quoi to an already tense atmosphere. The interlude hasn't hampered Djokovic because, as quick as a flash, he's at 40-0 and finishes the game with a spectacular running forehand winner, which curls around the post. Nadal thought he had won that point but the ball just bounced back from an irretrievable angle, just like a pesky boomerang.
http://news.bbc.co.uk/sport2/hi/tennis/9689082.stm