Answer: TABOO

Taboo refers to a social or cultural prohibition or restriction on discussing or engaging in certain actions, topics, or behavior. It is a subject or activity deemed inappropriate, offensive, or unacceptable within a particular society or group. When someone says "We don't talk about that," it suggests that the topic is considered taboo and should be avoided or kept private.

Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Don't mention it!. Explanations are generated by AI and may be inaccurate.