Fictitious means made up, or imaginary. No matter how real Scarlett O'Hara might seem in "Gone With the Wind," she's a fictitious character invented by author Margaret Mitchell.
When you look at the word fictitious, you'll probably notice that it bears a striking resemblance to fiction — which is an imaginary story about people and events that are made up for the purpose of entertaining readers. Fictitious can also be used to mean "trick or deceive." A thief assumes a fictitious name to hide his real identity and evade capture.