wear thin
To be weakened or eroded gradually

[TahlilGaran] Dictionary of Contemporary English ▲

wear thin
1.
if your patience wears thin, you become less and less patient.
I've warned you several times about being late and my patience is wearing thin.
(often in continuous tenses)
2.
if a joke, an excuse, or an explanation wears thin, it becomes less effective because it has been used too much.
This excuse about not having enough staff to run the trains is wearing rather thin, don't you think?
(often in continuous tenses)

[TahlilGaran] English Idioms Dictionary ▲

wear thin
1. become thin from use or the passing of time
The silver dollar began to wear thin after it was in use for many years.

2. grow less interesting or believable
His excuses began to wear thin after he kept using them again and again.

[TahlilGaran] English Idioms Dictionary ▲

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.

[TahlilGaran] English Idioms Dictionary ▲