corporate slave; corporate drone
Jocular, self-deprecating term for an employee who sacrifices personal life for the company, often working excessive overtime. Compare 家畜 (livestock).
See also: 家畜
With all the overtime, I've completely turned into a corporate slave.
He works until the last train every day; he's a total corporate slave.
I want to escape the corporate drone life.
He works like a corporate slave until late every night.
家畜 literally means 'livestock' or 'domestic animal', and 社畜 is a punning coinage that swaps 家 (home) for 社 (company) to mean an overworked employee treated like livestock.
A blend of 会社 “company” and 家畜 “livestock,” coined around 1990 by the novelist 安土敏 for an employee subordinated completely to a company.