Which term means to cause a loss of affection or friendliness?

The term that signifies causing a loss of affection or friendliness is "disaffect." This word originates from the prefix "dis-" which indicates a reversal or negation, combined with "affect," which refers to feelings or emotional connections. Thus, to disaffect someone means to alienate them or create a rift in what was once a positive or friendly relationship.

In contrast, "disparage" means to belittle or speak of someone or something in a way that shows strong disapproval, which can undermine someone’s reputation. "Discomfit" refers to a state of discomfort or embarrassment, often relating to thwarting someone’s plans or efforts. "Disturb" generally signifies causing disruption or interruption, affecting tranquility or order but does not inherently pertain to the emotional bonds as "disaffect" does.

Understanding the contexts of these words clarifies how "disaffect" specifically pertains to altering relationships, making it the appropriate choice for this question.