There is no grammatical gender in the English noun. The word benefactress may be used for a female benefactor, but it is not necessary except to specify the person's gender, which of course is a form of sexism.
benefactress
Malefactor
Clot is not gender specific.
The opposite gender of fraternity is sorority.
The opposite of dairymaid is dairyman.
Cock's opposite gender is hen.
benefactress
That would be a benefactress.
Benefactor is technically gender neutral, but benefactress is a specifically feminine form of the word.
Malefactor
Doctor is a neuter gender
Clot is not gender specific.
The opposite gender of fraternity is sorority.
An emperor is the opposite in gender to an empress.
Opposite gender of Filipino: Filipina
The opposite gender to "negro" is "negra" in Spanish, which translates to "black" and "black woman" respectively.
The opposite gender of boy is girl. Boys are male, while girls are female.
The opposite gender of giantess is giant.