The female version (seldom used today) is "testatrix."
In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.The noun 'testatrix' is a gender specific noun for a female who makes a will.The gender specific noun for a male who makes a will is testator.The noun 'testator' is also a common gender noun as a word for any person who makes a will.
Doctor is a neuter gender
Opposite gender of Filipino: Filipina
Clot is not gender specific.
Opposite gender of a Filipino: FILIPINA
The opposite gender of farmer is farmeress or farmwife.
The opposite gender of fraternity is sorority.
An emperor is the opposite in gender to an empress.
The opposite gender of giantess is giant.
The opposite gender for Joseph is Josephine.
The masculine form for testatrix is testator. A testator is a person who makes a will.