Finding synonyms for the word "second-rate" can be helpful to avoid repetition in writing or speaking. Some possible alternatives include mediocre, inferior, subpar, average, ordinary, middling, and substandard. These words suggest something that is not up to the expected standard or quality. "Mediocre" implies that something is only average or ordinary, while "inferior" suggests that it is of lower quality than something else. "Subpar" implies that something is below average, while "substandard" suggests that it fails to meet the required standard. "Average" and "ordinary" are less negative but still imply that something is not exceptional or outstanding. "Middling" suggests that something is neither great nor terrible, while still being below average.