This is the 4252nd most frequent Japanese word.
使い古し
"使い古し" means "worn-out" or "used-up."
In this sentence, '使い古し' is used to describe the sense or appearance of being worn out through extensive use.
この古いカバンは使い古した感じがある。
This old bag feels worn out.
Here, '使い古し' refers directly to the state of the shoes being worn out from usage.
その靴は使い古しなので、新しいものを買うべきだ。
Those shoes are worn out, so you should buy new ones.
In this example, '使い古し' indicates that although the pen is extensively used or worn, it retains functionality.