After a 1NT opening by Opp, your P has overcalled with 2♣ : Landy Convention
This overcall is a very efficient way to bid a minimum 2-suiter in the majors :
- A 2-suiter and at least 5-4 in the major suits
- In general with a minimum point count approx 10HCP Sometimes if the vulnerability is favorable, then the strength of the 2-suiter which is 5-5 can be a bit less.