The DICT Development Group

  Taboo \Ta*boo"\, a. [Written also tabu and tapu.]
     [Polynesian tabu, tapu, sacred, under restriction, a
     prohibition.]
     Set apart or sacred by religious custom among certain races
     of Polynesia, New Zealand, etc., and forbidden to certain
     persons or uses; hence, prohibited under severe penalties;
     interdicted; as, food, places, words, customs, etc., may be
     taboo.
     [Webster 1913 Suppl.]