Mrs. Erlynne, the real mother of Lady Windermere is what we can catalogue as an AMORAL person. We could argue that she is innately a bad person because she is a blackmailer, after all, has very little interest in making a meaningful connection with her daughter and, most importantly, has a very tainted past which ended in her expulsion from the acceptable society.
However, we cannot completely render this veredict as one and only, because in her mind Mrs. Erlynne simply does not see those things as good or evil, but merely as tactics for social survival.
Therefore, although Mrs. Erlynne is certainly not a good woman, we cannot say that she is bad. She is amoral in that she does the things that she does "just because". She needs money? she gets it the easiest way. She wants company? She manipulates people to get it for her. But her lack of worry and lack of guilt helps us realize that, to her, none of those things are unacceptable, but reasonable to consider.