The phrase "having that certain something" is commonly used to describe someone or something that possesses a certain charm or attraction that is hard to define. Some synonyms for this phrase include appeal, allure, charisma, magnetism, enchantment, fascination, and "je ne sais quoi" (a French term meaning "an indescribable something"). Other similar phrases include "X factor," "magic touch," and "special sauce." These words and phrases can be used interchangeably to describe someone's unique qualities that make them stand out and easily attract attention. With these phrases, you can effectively convey the specific charm that someone or something has in a single expression.