A more thorough explanation:

Decrepit (di-krep-it) is an adjective used to describe a person who is physically or mentally disabled to such an extent that they would be helpless in a personal conflict with a person of ordinary health and strength.

• The old man was so decrepit that he could barely walk without assistance.
• After the accident, the athlete was left decrepit and unable to compete again.
• The woman's mental health had deteriorated to the point where she was decrepit and unable to care for herself.

These examples illustrate how a person who is decrepit is unable to function normally due to physical or mental limitations. They require assistance and are vulnerable in situations where they may need to defend themselves.