Athenomasc is a synonym to transmasculine.
The transfeminine equivalent is apollafem.
History
Athenomasc was coined by reddit user u/yahahawei on August, 17th, 2022 as an alternative to transmasculine, this term more represents always being male/masculine but having the knowledge/experience of the opposite gender.[1]
Flag
The flag was made by the same user on the same day, The full blue/teal design represents being masculine/male 100% with the symbol of Athena the Goddess of wisdom on it to represent the wisdom of the other gender.