There are many synonyms for the expression "day's work." One alternative is "daily labor," which emphasizes the physical or manual aspects of the work performed. Another option is "daily task," which can imply a more routine or bureaucratic set of responsibilities. "Daily grind" is a more pejorative way to refer to one's daily work routine. "Job," "occupation," and "profession" all serve as synonyms for work or employment more generally, not necessarily just the tasks performed in a given day. "Shift," "duty," and "responsibility" can all refer to a specific period or set of tasks within the larger workday.
