Obsessive-Compulsive Disorder (OCD) is often reduced in everyday conversation to "being a neat freak" or "liking things organized." Clinically, OCD is very different, and often far more distressing than that description suggests.
OCD involves two connected parts: obsessions (unwanted, intrusive thoughts, images, or urges that cause significant anxiety) and compulsions (repetitive behaviors or mental acts performed to reduce that anxiety, even though the relief is usually brief). Common themes include fears of contamination, harm, or things not being "just right," but OCD can attach itself to almost any subject.
What distinguishes OCD from ordinary habits or preferences is the level of distress involved and how much time and energy the obsessions and compulsions consume, often an hour or more a day, interfering with work, relationships, or daily routines.
The good news is that OCD responds well to structured treatment. Cognitive Behavioral Therapy, particularly a technique called Exposure and Response Prevention, along with medication management where appropriate, can meaningfully reduce symptoms.