The term "undefeated professionally" suggests a person or team who has never lost a professional competition. Synonyms for this phrase may include "unbeaten," "victorious," "invincible," "dominant," and "untouchable." These words all convey a sense of superiority and dominance over opponents. Other related terms may include "champion," "winner," "undefeatable," and "undefeased." These synonyms can be used to describe individuals or groups who have achieved a high level of success and power in their careers or sports. Overall, the use of these synonyms highlights the achievement and accomplishment of those who have never been defeated professionally.