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.
Malefactor
Clot is not gender specific.
The opposite of dairymaid is dairyman.
Mistress is the opposite gender of master.
Newswomen is the opposite gender of newsmen.
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
Opposite gender of Filipino: Filipina
Clot is not gender specific.
Opposite gender of a Filipino: FILIPINA
An emperor is the opposite in gender to an empress.
The opposite gender of giantess is giant.
The opposite gender for Joseph is Josephine.
There isn't an opposite gender of farmer. A farmer can be either a male or a female.