Feminafidem was coined by Cryptocrew on February 2nd of 2021 in order to describe their experiences. Lots of transfeminine Christians are told they can't be both and that they have to choose either being Christian or being transgender, however, this is untrue.
Femina is woman in Latin while fidem is faith in Latin.
The feminafidem flag is just the trans woman pride flag with a Christian cross superimposed to represent Christian trans women. It was designed by Rainbowraven96 (now Reign of the breadsticcs) on February 7, 2021.