Worn out, like US cars? (5)
I believe the answer is:
tired
'worn out' is the definition.
(similar in meaning)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tired that I've seen before include "Spent" , "ready for bed" , "Worn out" , "Beat" , "Weary, jaded" .)