What is the feminine form of the word 'Traitor'?

• Traitor:
English meaning: a person who gives away or sells secrets of his or her country, or someone who is not loyal to particular beliefs or friends.
Bangla meaning: বিশ্বাসঘাতক।
- এর feminine gender হচ্ছে: Traitress:  বিশ্বাসঘাতকিনী।
- Masculine gender এর শেষে 'or, er, ar'  থাকলে Feminine form 'o, e, a' উঠে গিয়ে r এরপর -ess যুক্ত হয়।

Source: Accessible Dictionary y Bangla Academy.