As an adjective, taboo means ‘forbidden or prohibited’. The word is typically applied to what is forbidden or prohibited because it violates a social or cultural convention (rather than because it is, e.g., illegal or morally wrong), Hence, though the violation of a taboo may elicit strong feelings of disapproval, what is taboo varies from one social group to another - what is taboo in one group may be perfectly acceptable in another. (The word taboo has a slightly broader use in the social sciences: for this consult a reliable textbook.)
Some examples of what is taboo in the UK:
- taboo words - slang words for male and female genitalia (such as ‘cock’ and ‘fanny’) and slang words for sexual intercourse (such as ‘fuck’ and ‘shag’.). (A significant proportion of the UK population would find the use of these words offensive.)
- taboo topics - it is sometimes said that there are three taboo topics of conversation at middle-class dinner parties - sex, politics, and religion. (All three are topics which, in different ways, may lead to embarrassment and/or heated argument, and so are inimical to a relaxed and friendly atmosphere among the guests.)
- taboo actions and activities: a visitor to an Oxbridge college might be told that walking on the lawns is taboo. (This is because walking on the lawns is a privilege reserved for a select group, e.g., Fellows of the College, and those who are not members of this group should not encroach on this privilege.)
- As a noun, a taboo is a prohibition (e.g., ‘There is a taboo on talking about such contentious matters’), while as a verb it means ‘to place a taboo on’ (e.g., ‘The chairman said before the meeting that he would taboo any discussion of the company’s financial situation.’).
- Etymological note: The word taboo entered the English language in 1777 when the English explorer Captain James Cook (1728-1779), on his third voyage of exploration to the Pacific, landed on the island of Tonga and in describing certain aspects of the islanders’ behaviour used the native word tapu, which he wrote as taboo, and understood to mean ‘forbidden’.