Yes, you can if you connect to MySQL using a UNIX socket.
You can say that the user will be identified by the OS user of the accessing application rather than by the MySQL username and password.
CREATE USER username@hostname IDENTIFIED VIA unix_socket;
If your application connects to the MySQL socket, MySQL will ask the OS who is currently connecting to the socket and the OS will tell MySQL what user is on the other end. That way, MySQL will authenticate your application without any password.
The attacker will first have to assume the OS user identity in order to access the DB. Which means that when you talk about the OS Administrator, then they have the right to pretend to be any user and you can't hide anything from them.
But they will never see the password in plain text as you requested. Because there is no password to authenticate your application.
Another option would be if your application is persistent. For example, a Node server. You can make the server to read typed password at startup. The server will store it in memory and it won't be in any persistent storage. An experienced administrator can dump the app memory and find it, but you can encrypt it in memory with randomly generated salt, which will be harder to find. But not impossible. It will just require more technical skills, and I bet the people who have them are on a different level so they won't be into hacking low-value targets.
But again - there is no defense against skilled OS Admin having full access to your app files and memory. But dumb admins, there is a chance with in-memory stored passwords (unless they are able to use terminal monitoring software that logs all what is happening in CLI). So again. Don't expect to hide from people whose services you use (OS admins, hosting companies, VPN proxies, etc.).