pseudopatient
/ˌs(j)uːdəʊˈpeɪʃnt/ /ˈs(j)uːdəʊˌpeɪʃnt/noun
A false or spurious patient; specifically (in early use) a person feigning illness to obtain some benefit; (later) a person posing as a patient in order to investigate health care, provide training to medical staff, etc.
Origin
Mid 19th century. From pseudo- + patient.