Taboo
WordNet
adjective
(1) Excluded from use or mention
"Forbidden fruit"
"In our house dancing and playing cards were out"
"A taboo subject"
(2) Forbidden to profane use especially in South Pacific islands
noun
(3) An inhibition or ban resulting from social custom or emotional aversion
(4) A prejudice (especially in Polynesia and other South Pacific islands) that prohibits the use or mention of something because of its sacred nature
verb
(5) Declare as sacred and forbidden