The phrase "not real" is commonly used to describe something that is imaginary, fictitious, or non-existent. However, there are many different synonyms that can be used to convey this concept, depending on the context in which it is being used. Some of these synonyms include unreal, imaginary, fake, counterfeit, illusory, fictional, make-believe, fabricated, and artificial. Each of these words carries its own subtle nuances and connotations, and can be used to convey different shades of meaning. For example, "fictional" may be used to describe a character in a story, while "illusory" may be used to describe a mirage or optical illusion.