When it comes to describing a task that is difficult to accomplish or requires a lot of effort, there are several synonyms that can be used instead of "hard job." For example, you could use "challenging task," "arduous work," "demanding role," or "complicated project" to convey a similar meaning. Other viable options include "laborious assignment," "difficult undertaking," "taxing mission," or "tricky responsibility." Depending on the context, you could also use phrases like "onerous duty," "testing job," or "tough job" to describe a task that is particularly challenging or demanding. Ultimately, the key is to choose a synonym that accurately reflects the nature of the task at hand.