Other forms: empty suits
An empty suit is someone who appears powerful, wise, or competent, but is actually not very good at their job. A sharp-dressed senator who has never accomplished anything on Capitol Hill might be criticized as an empty suit.
An authority figure who dresses appropriately but is completely ineffective is an empty suit. Imagine a school principal who walks around looking just like a principal should, wearing exactly the right outfits, but is absolutely terrible at the job. This derogatory term empty suit comes from the idea of a person having no real substance beneath the suit they wear.