Etymology:
–1777 (in Cook’s “A Voyage to the Pacific Ocean”), “consecrated, inviolable, forbidden, unclean or cursed,” explained in some English sources as being from Tongan (Polynesian language of the island of Tonga) ta-bu “sacred,” from ta “mark” + bu “especially.” But this may be folk etymology, as linguists in the Pacific have reconstructed an irreducable Proto-Polynesian * tapu, from Proto-Oceanic * tabu “sacred, forbidden” (cf. Hawaiian kapu “taboo, prohibition, sacred, holy, consecrated;” Tahitian tapu “restriction, sacred;” Maori tapu “be under ritual restriction, prohibited”). The noun and verb are English innovations first recorded in Cook’s book.
—Etymology online
The word itself (taboo) is used in more than one signification. It is sometimes used by a parent to his child, when in the exercise of parental authority he forbids it to perform a particular action. Anything opposed to the ordinary customs of the islands, although not expressly prohibited is said to be “taboo”.
–Herman Mellville, Typee
Some taboo activities or customs are prohibited under law and transgressions may lead to severe penalties. Other taboos result in embarrassment, shame, and rudeness. Although critics and/or dissenters may oppose taboos, they are put into place to avoid disrespect to any given authority, be it legal, moral and/or religious.
—Wikipedia
We find many things to which the prohibition of them constitutes the only temptation.
–William Hazlitt