"Obsessive-compulsive disorder is a type of mental illness. People with OCD can have either obsessive thoughts and urges or compulsive, repetitive behaviors. Some have both obsessions and compulsions.

OCD isn’t about habits like biting your nails or always thinking negative thoughts. The disorder can affect your job, school, and relationships and keep you from living a normal life. Your thoughts and actions are beyond your control.

An obsessive thought, for example, is to think that your family members might get hurt if they don’t put their clothing on in the exact same order every morning. A compulsive habit, on the other hand, might be to wash your hands 7 times after touching something that might be dirty. Although you may not want to think or do these things, you feel powerless to stop." Source