A person of substance is someone who is significant, important, or distinguished. They have substance, meaning they possess qualities such as intelligence, competence, and integrity. Synonyms for this term include a bigwig, a heavyweight, a luminary, an influencer, a VIP, a notable, a leader, a tycoon, a magnate, or a titan. These are people who have achieved great success in their field, and are looked up to by others in their industry. A person of substance is not just someone who is wealthy or powerful, but rather someone who is respected for their accomplishments, knowledge, and character.