If you describe someone as a ~, you mean they refuse to believe something until they see definite proof or evidence of it.
N-COUNT
If you describe someone as a ~, you mean they refuse to believe something until they see definite proof or evidence of it.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012