The term ‘evolutionist’ is used loosely and interchangeably by creationists for:
any scientist or academic whose work has any connection, however tenuous, to evolution or the age of the Earth or whose work somehow contradicts the theology of the person using the term;
anyone who believes in common descent (including Old Earth Christians);
atheists (even though not all evolution-believers are atheists).
This site uses the term similarly loosely in places to cover the first two meanings.