As I've written previously, there are plenty of imported words used in Japan that have very different meanings from the original. This happens to a lesser extent in the opposite direction, but it does indeed happen. One notoriously mangled word is 禅 - Zen.
In Japanese 禅 refers to a branch of Buddhism (仏教 ぶっきょう bukkyou). Certain rituals connected with Zen Buddhism have been embraced by non-Zen Buddhists, such as the practice of meditation while in 座禅 ざぜん(zazen) pose, or the refined vegetarian cuisine developed by some Zen Buddhist monks called 精進料理 しょうじんりょうり (sho-jin ryouri). But the word Zen seems to have taken a life of its own in the west, specifically in English, to mean anything from simple and uncluttered or vaguely 'enlightened', to anything remotely Asian or 'Oriental'.
In Japanese, the word Zen is never used in this way. So, if you would try to say something like あなたの部屋はとても禅ですね あなたのへやは とてもぜんですね (your room is very Zen), most likely you'll get a puzzled look in return.
Personally, when I hear the word Zen bandied about so trivially it annoys me a bit because it smacks of pop-Zen. But then, I'm rather easily annoyed. I must achieve a Zen State or acquire Zen Habits or something, I suppose.
See also: Kaizen, or ooh, those inscrutable Japanese.