Melvin Udall is a fictional character from the 1997 film "As Good as It Gets," portrayed by actor Jack Nicholson. He is a successful but misanthropic author who struggles with obsessive-compulsive disorder (OCD) and has difficulty forming relationships with others. His character is known for his sharp wit and often abrasive demeanor. Throughout the film, Melvin undergoes significant personal growth as he interacts with other characters, including a waitress named Carol Connelly, played by Helen Hunt, and a gay artist named Simon Bishop, portrayed by Greg Kinnear. These relationships challenge his worldview and ultimately lead him to confront his own vulnerabilities.