I'm using windows and I'm using ubuntu in wsl's linux environment to study Ruby on Rails.
The database uses PostgreSQL, but I made a mistake when setting the user name, and an unnecessary user was set. Therefore, I want to delete the user name that I no longer need.
I would appreciate it if anyone could teach me.

Unnecessary user name ({imoto} is unnecessary.) What I tried

I did dropuser {imoto} and drop role {imoto}, but it didn't work.

Supplementary information (FW/tool version, etc.)

Please provide more detailed information here.