In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.
In English, the noun 'kaiser' is a gender specific noun for an emperor of the Austrian Empire (1804-1918) and the German Empire (1871-1918). There were no females holding the office throughout this period.
There is no corresponding gender specific noun for a female emperor. The wife of a kaiser is called a kaiserin.
Many people will state that the feminine form of Kaiser is Kaiseress. However this is not actually true. Because Kaiser is a German word, the actual feminine form is Kaiserin - the official title given to a female German Kaiser.
The feminine form of ami is amie. The feminine plural is amies.
The feminine form of bajo is baja. The feminine plural is bajas.
The feminine form of alumnus is alumna. The feminine plural is alumnae.
Baroness is the feminine form.
Mistress is the feminine form of master. It is already in feminine form.
The feminine form of charmant is charmante. The feminine plural is charmantes.
The feminine form for host is "hostess."
The feminine form of benefactor is benefactress.
The feminine form of "mauvais" is "mauvaise."
Ta means "your" before a feminine, singular noun.
The masculine form of "duke" is "duke," and the feminine form is "duchess."