"Grind away" is a common phrase that is used to describe putting in consistent effort towards a task or goal. However, there are several synonyms that can be used to convey the same message. Some of the words that can be used as a replacement for "grind away" include toil, labor, strive, persevere, and slog. These words all imply consistent and dedicated effort towards a task or goal. Additionally, words such as grind, work hard, exert, and buckle down can also be used in place of "grind away". Ultimately, the choice of synonyms depends on the desired tone and context of the sentence and overall message trying to be conveyed.