wear thin

wear thin  {v.}
1. To become thin from use, wearing, or the passing of time.
My old pair of pants has worn thin at the knees.
This old dime has worn very thin.
2. To grow less, or less interesting; decrease.
The joke began to wear thin when you heard it too many times.
The teacher's patience began to wear thin when he saw that no one knew the lesson.
Categories: time verb