A cluttered desk is a source of stress.

Meaning: This means that a messy and disorganized desk can make you feel stressed and anxious.

Choice of Words: Cluttered means filled with many things in a disorganized way. Source means the origin or cause of something. Stress means a state of mental or emotional strain or tension. When you combine them, "A cluttered desk is a source of stress" means that a messy and disorganized desk can cause stress.