taboo - noun

a prejudice (especially in Polynesia and other South Pacific islands) that prohibits the use or mention of something because of its sacred nature

an inhibition or ban resulting from social custom or emotional aversion

taboo - verb

• declare as sacred and forbidden

taboo - adjective

• excluded from use or mention
• forbidden to profane use especially in South Pacific islands

taboo - thesaurus

forbidden   out   prohibited   proscribed   tabu   verboten