Female to Male
From BDSM Wiki
A person who was assigned to the binary gender of female at birth, but identifies as male.
A FtM identifying person may or may not have started hormones or surgeries. A person may not wish to undergo the procedures, as they are comfortable in their current body, despite their gender identity. This does not mean they do not identify as male or that they should be treated as female.
Proper communication etiquette says to use their chosen pronouns and refer to them as a male.