Literally: phonetic “na” – phonetic “mu” – three – treasure
Alternately: Roughly equivalent to “Oh my God!” in Western exclamatory parlance, this phrase is supposedly used to invoke the aid of the Buddha when one has messed up. My sources all use the term 失敗 (shippai; “mistake”), suggesting that the phrase is used in times of personal failure rather than in the face of the world’s external vicissitudes. It also seems that the phrase is best used when one is caught off-guard by one’s errors, rather than when they’ve been seen coming for a while.
Alternately, this phrase may be invoked for divine protection, to ensure success in a risky venture.
Notes: This deeply Buddhist phrase is obviously not going to be used very much in modern, secular society.
Namu is a transliterated Sanskrit word; apparently it means something like “Hail,” and is often used before the Buddha’s name to indicate respectful address. The phrase seems to have been popularized somewhat by a 1975-82 anime series about a precocious Zen monk folk hero called Ikkyū. Sanbou, as one can guess from the literal meaning of the characters, refers to the “three treasures” of Buddhism: the Buddha, the sutras (or, the Buddha’s teachings), and the priesthood (who spread those teachings).