The phrase "affair of honour" is typically used to refer to a situation in which people, usually men, challenge each other to a duel in order to defend their reputation or personal honor. However, there are many other ways to express this concept in language, depending on the context and tone of the discussion. Some alternative synonyms for "affair of honour" might include "duel," "challenge," "dispute," "quarrel," "feud," "disagreement," or "conflict." Each of these words has its own subtle connotations and nuances, which can convey different shades of meaning and emotion depending on the speaker's intent and the circumstances of the situation.