Second rate and Second-class

Second-class and second rate are semantically related. in low topic. In some cases you can use "Second-class" instead an adjective phrase "Second rate", when it comes to topics like inferior, poor, mediocre.

Second-class adjective - Of little or less value or merit.

Second rate and second-class are semantically related. Sometimes you can use "Second rate" instead an adjective phrase "Second-class".