this type of employee is someone who does work for an organization on a temporary or part-time basis
Temporary work Temporary work or temporary employment refers to an employment situation where the working arrangement is limited to a certain period of time based on the needs of the employing organization. Temporary employees are sometimes called "contractual", "seasonal", "interim", "casual staff", "outsourcing", "freelance"; or the word may be shortened to "temps". In some instances, temporary, highly skilled professionals (particularly in the white-collar worker fields, such as law, engineering, and accounting) refer to themselves as consultants.
Turnover (employment) Practitioners can differentiate between instances of voluntary turnover, initiated at the choice of the employee, and involuntary turnover initiated by the employer due to poor performance or reduction in force (RIF).