Unmentionable/ʌnˈmenʃənəbl/ Definition 1 of 2Pro Tip 1/3Sensitive Subjects Use 'unmentionable' to refer to topics usually avoided in polite conversation. He avoided the unmentionable details of the scandal. Pro Tip 2/3Cultural Awareness What's considered 'unmentionable' can differ across cultures; be mindful of this. In some cultures, discussing one's income is unmentionable. Pro Tip 3/3Emotional Impact Be aware 'unmentionable' may indicate a topic is not just taboo, but painful to discuss. The tragedy was unmentionable for her, even years later.