taboo word; forbidden topic
A word or topic that is socially or contextually off-limits; common in everyday conversation.
彼の前で離婚の話は禁句だ。
Talking about divorce is a taboo topic in front of him.
この会議では、給料の話は禁句になっている。
In this meeting, salary talk is a forbidden topic.
forbidden words (in classical poetry)
Original meaning: words or phrases prohibited in traditional waka and haikai poetry. Now a historical/literary term.
和歌では「涙」や「死」が禁句とされることがあった。
In waka, words like 'tears' and 'death' were sometimes considered forbidden.
The topic of divorce is off-limits in front of him.
At this company, talk of salaries is treated as a forbidden topic.
Bringing up her age is a no-go with her.