Demigirl Definition

“A demigirl (also called a demiwoman or a demifemale person) is a gender identity describing someone who partially, but not wholly, identifies as a woman, girl or otherwise feminine, whatever their assigned gender at birth. They may or may not identify as another gender in addition to feeling partially a girl or woman.”

                                              - Gender Wikia

There are lesser known definitions:

Demigirl can also describe someone who was assigned female at birth that feels disconnected to that identity.

                      Another definition is when someone who is assigned male at birth is transfeminine but not completely defined by the binary. They often feel more strongly with “female” than “male” but not strong enough to identify as a woman.