Final answer:
The designation that is not synonymous with social entrepreneur is social activist.
Step-by-step explanation:
Of the given options, the designation that is not synonymous with social entrepreneur is social activist. While social entrepreneurs aim to create sustainable solutions to social problems through entrepreneurial approaches, social activists are individuals who work towards raising awareness and promoting change regarding social issues, but they may not necessarily focus on the entrepreneurial aspect. Social innovator, public entrepreneur, and civic entrepreneur, on the other hand, are all designations that are synonymous with social entrepreneur as they involve the development and implementation of innovative solutions to social problems.