benefactress
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.
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
Opposite gender of Filipino: Filipina
Clot is not gender specific.
Opposite gender of a Filipino: FILIPINA
The masculine form of "benefactress" is "benefactor." A benefactor is an individual, typically a person of means, who provides financial support or assistance to a person, organization, or cause. While "benefactress" specifically refers to a female benefactor, "benefactor" is a gender-neutral term that can refer to anyone who provides such support.
There isn't an opposite gender of farmer. A farmer can be either a male or a female.
An emperor is the opposite in gender to an empress.
The opposite gender of giantess is giant.