Self-styled (adjective)

1. Designating oneself as having a certain title, status, or role, without any external validation or recognition.
2. Designating oneself as having a certain style or manner.

Origin:

Composed of the word "self" meaning "oneself" and "styled" meaning "having a certain style or manner".

Examples:

1. He was a self-styled expert on the subject, but had no formal qualifications.
2. She was a self-styled leader, but had not been elected by her peers.
3. The self-styled king had no real power or authority.
4. He was a self-styled genius, but his ideas were not well-received.
5. She was a self-styled fashion icon, but her sense of style was questionable.