Devil's advocate is a phrase that refers to someone who takes a position for the sake of argument. There are several synonyms that can be used for this expression, such as sceptic, contrarian, dissident, nonconformist, oppositionist, or antagonist. These words generally describe somebody who takes an opposing stance to the norm, questioning assumptions, and challenging ideas. Devil's advocates often play a crucial role in constructive debates, as they can help to identify any weaknesses or flaws in an argument. However, it's essential to note that being a devil's advocate can sometimes be viewed as negative, particularly if you consistently take opposing views without offering any constructive feedback.