Is a woman's accusation against another woman that she exposes her 'awrah to the laundryman considered qadhf (slanderous accusation) necessitating legal proof or resulting in a religious ruling?

What the Muslim woman said about her Muslim sister is forbidden and not permissible, whether she was truthful or a liar. The duty is to conceal a Muslim, and there is no benefit in mentioning this. This statement is not slander (qadhf), as qadhf is explicitly or implicitly accusing someone of adultery. However, the accused has the right to demand proof from the one who accused her, and if the accuser fails to provide proof, she deserves disciplinary punishment (ta'zeer).