Kūki o yomu (空気を読む): reading the air. The Daijisen dictionary defines it as inferring the situation from the atmosphere of a place, and especially judging what one should and should not do, and what others want and do not want.
In 2007, the abbreviation KY, for kūki yomenai, “cannot read the air,” was among the nominees for the year’s buzzword award, the Shingo Ryūkōgo Taishō.