Mediator. There is no separate form. In most cases, feminine versions of words like executrix have gone out of use, while executor is applicable to both genders.
There is no word for the term mediator in the Somona (correctly spelled Samoan) language. There is an estimated
Countess is the feminine term
Landlady
Poetess
Poetess.
Heroine
feminine term of villain
"Singe" is a neutral term in French and does not have a specifically masculine or feminine form.
There is no feminine version of the word "hound". The proper term for any female dog is "bitch".
You could have a Legal Mediator Career. You can find information at http://occupations.careers.org/8405/legal-mediator
Nanny goat or doe.