Here's a breakdown:
* Wits: Refers to your intelligence, understanding, and ability to think clearly.
* End: Indicates the limit of your abilities or resources.
Example: "After days of searching for my lost keys, I was at my wits' end."
Other expressions with a similar meaning:
* At the end of your rope
* At your breaking point
* At the edge of your sanity
* At the end of your tether
These phrases all express a state of extreme frustration, exhaustion, and helplessness.