A "hermi" is a hermaprodite. It has both male and female flowers. Hermies are generally bad news. They create polen and polinate any female plants nearby, and they always self polinate, so they create useless buds. Unless you're doing some fancy seed creating, they have no real use.
Hello superstar the more you stress a plant the more likely it will turn hermie a pollinated plant isn't useless it will still produce smokeable bud but the plant will put most of its energy into producing seeds therefor its good to avoid any males/hermie.