ANSWER:
Such a woman is sinful and ignorant, however, it is not permissible to make takfeer on individuals as this can only be done by a Muslim judge or ruler. Giving takfeer like this is a trademark of khawarij. One can’t give takfeer to individuals without ensuring that the conditions are fulfilled and that there are no obstacles preventing takfeer from taking place. Besides, why would you follow and watch such an imbecile?