After an overcall, a cue bid of the opponent’s suit by either member of the opening side asks partner to bid no-trumps if he holds a partial stopper (or better) in the opposing suit. To make such a bid it would be usual to hold a partial stopper oneself.
For example:
![](https://bernardmageebridge.com/wp-content/uploads/2021/11/image-77.png)
![](https://bernardmageebridge.com/wp-content/uploads/2021/11/image-78.png)