noun
playing doctor; playing doctor and patient
A children's pretend game where one child acts as a doctor and another as a patient. The term is a compound of お医者さん (doctor, polite) and ごっこ (make-believe play).
子供たちはお医者さんごっこをして遊んでいた。
The children were playing doctor.
ごっこ遊び is the general term for make-believe play, while お医者さんごっこ specifies the doctor game.
Compound of お医者さん (doctor, polite) + ごっこ (make-believe play). The suffix ごっこ derives from the verb ごっこする, meaning to pretend or play at something.