A tidy desk is a reflection of a healthy mind.

Meaning: This means that a neat and orderly desk can show that you are mentally healthy and organized.

Choice of Words: Tidy means neat and orderly. Reflection means something that shows or indicates something else. Healthy means in good physical or mental condition. When you combine them, "A tidy desk is a reflection of a healthy mind" means that a neat and orderly desk can be a sign of a healthy and organized mind.