taboo

1. N-COUNT A taboo against a subject or activity is a social custom to avoid doing that activity or talking about that subject, because people find them embarrassing or offensive. 禁忌

The topic of addiction remains something of a taboo in our family. 毒瘾在我们家依然是个有些忌讳的话题。

2. ADJ Taboo is also an adjective. 禁忌的

Cancer is a taboo subject and people are frightened or embarrassed to talk openly about it. 癌症是个禁忌的话题，人们对公开谈论它感到害怕或尴尬。