Second-rate and Second rate

Second-rate adjective - Of average to below average quality.

Second rate and second-rate are semantically related In some cases you can use "Second rate" instead a noun phrase "Second-rate".

Second-rate and second rate are semantically related in one who finishes second topic. You can use "Second-rate" instead the phrase "Second rate" as an adjective or a noun, if it concerns topics such as below normal, very bad, lousy, minor league.