ruupii, "loopy".
Needless to say, in English this is an unrefined expression. In fact I rarely had a chance to hear any one used this word in the real life. However, this now may newly join into Japanese. At this moment, it has a very limited usage, that is to criticize the Prime Minister. It first appeared on an American news column, and somehow it matches the frustration that many people feel about this political leader, and two days ago, a member of the Diet even shouted it while the Prime Minister was making a speech in the Diet.
New katakana words are created all the time. Here, we are observing one unique moment.