temporary worker; dispatched employee
A worker sent by a staffing agency to work at a client company. Similar to 派遣社員, but 従業員 is a broader term for employee.
See also: 派遣社員
He works at a major company as a dispatched employee.
派遣社員 is a more common term for a dispatched worker, often used in contrast with regular employees. 派遣従業員 is a broader term that can include non-office workers.
Compound of 派遣 (dispatch) and 従業員 (employee).