A total prohibition of intercourse with, use of, or approach to, a given person or thing under pain of death, -- an interdict of religious origin and authority, formerly common in the islands of Polynesia; interdiction. [Written also tabu.]

Ta·boo
v. t.

[imp. & p. p. Tabooed ; p. pr. & vb. n. Tabooing.]
To put under taboo; to forbid, or to forbid the use of; to interdict approach to, or use of; as, to taboo the ground set apart as a sanctuary for criminals. [Written also tabu.]

Webster 1913 Dictionary edited by Patrick J. Cassidy