noun
contract work
Work performed under a contract, often on a project basis rather than as a regular employee.
彼は請負仕事で生計を立てている。
He makes a living doing contract work.
請負 is the broader term for contracting or undertaking a job, while 請負仕事 specifically refers to the work itself.
Compound of 請負 (ukeoi, 'contract') + 仕事 (shigoto, 'work').