Acting a part is a common phrase that refers to portraying a specific character or behavior. However, there are various synonyms for this phrase that can be used in different contexts. One synonym for "act a part" is to "role-play," which is often used in gaming or therapy situations. Another equivalent term is to "emulate" or "imitate," which can be used to describe copying someone's actions or personality. "Mimic" and "impersonate" are also synonyms that can refer to acting a part, often used in comedic or theatrical settings. Ultimately, the use of synonyms for "act a part" depends on the desired tone and context of the sentence.