A demiboy is a gender identity that is within the non binary spectrum where a person partially identifies as being male.
When someone is a demiboy is basically means that the person feels a connection to masculinity but not fully.
The person identifying as a demiboy may also identify with other genders or no gender at all.
Essentially the person may only partly identify as a boy or man, regardless of the persons assigned sex at bight.
A demiboy feels a partial connection to the male gender but not a full or complete connection.
Like a demigirl, a demiboy may identify this way regardless of their assigned gender.
A demigirl and demiboy fall under the trans umbrella.
Basically demiboy is a gender that is partially male, and partially another gender or genders.
Partially male, and partially nothing or non binary is also defined as a non binary.