adjective.banned on grounds of morality or taste

• the subject is taboo
• Treatments outside the statistically proven are considered taboo …

adjective.banned as constituting a risk

adjective.forbidden for nonreligious use or contact because of what are held to be dangerous supernatural powers

noun.a prohibition imposed by social custom or as a protective measure

• … they may have developed a taboo against eating fish.
• … the tacticians in a conservative Republican Administration now deem membership in the club a taboo.

noun.something that is not acceptable to say, mention, or do: something that is taboo

noun.a prohibition against touching, saying, or doing something for fear of immediate harm from a supernatural force

verb.to set apart as taboo especially by marking with a ritualistic symbol

verb.to avoid or ban as taboo