taboo
ta-boo
noun
A social or religious custom forbidding a particular practice or association.
"Discussing death was a taboo in her family."
adjective
Forbidden or prohibited by social custom or religious practice.
"Certain topics remain taboo in polite conversation."
verb
To prohibit or forbid something, often by social or religious custom.
"The elders tabooed hunting in the sacred forest."
Thesaurus
Synonyms: sacred, tabu, forbidden, impermissible, proscribed, prohibited, verboten, out