Second-rate (8)
I believe the answer is:
mediocre
'second-rate' is the definition.
(I know that second-rate can be written as mediocre)
This is all the clue.
(Other definitions for mediocre that I've seen before include "Average (but poor)" , "Second-rate, undistinguished" , "Somewhat inferior" , "Not very good" , "Of unexceptional quality" .)