Defriend in a dream typically means that your social bond with this person has been severed in reality. Maybe because of your neglect to communicate or meet up as friends, they have cooled off and gradually drifted away from you. This old friendship is simply lost without warning.
The most common underlying source of defriending anxiety in a dream is a person’s self-doubt – you feel like you deserve to be around or be valued as people who are living their best life, rather than giving all their time to an unappreciated caretaker role and sacrificing their chance for happiness for others’ needs.
On the other hand, when someone defriends you in real life it is both hurtful and disrespectful, but in a dream it can be a symbol that something else is happening that you cannot see. We should keep in mind both the language used and the frequency of contact between your friendships before you jump to conclusions.