HeadMate 

A headmate is an "Alter" of someone who has Dissociative Identity Disorder. A headmate is their own person who has split off from the original person's mind, who has their own separate wants, goals, needs, gender, age, etc.

These headmates are usually formed as a coping mechanism, helping the person with DID to survive the traumatic experiences that they have been a victim to. A collection of headmates including the host is called a Multiple/Median System.

Due to the large amount of systems on Tumblr, it has been wrongly labelled as a "Tumblr trend" and been accused of mocking mental illness, despite it being a mental disorder in itself.

headmate,alter,DID,dissociative identity disorder,mental illness,tumblr,system,multiple,

HeadMate by 6yrhters April 24, 2016

Headmate 

Someone who shares a physical body with one or more people, or someone in a plural system. This term was coined by non-traumagenic systems, though it can be used by any kind of plural system.

A headmate is also sometimes known as an alter (though mostly in traumagenic systems), or simply system members.

“We got a new headmate today.”

Headmate by sonderwrites September 22, 2020

HeadMate 

An alternate personality or identity living in your head. Similar to a roommate or a house mate, but inside your skull. A person who describes themselves as having headmates is saying that they have people living in their heads who they have conversations with.

Some people can claim different ethnicities or sexualities, thus allowing them to join an autonomous caucus (for instance queer or women’s) that they were not otherwise entitled to join.

When they are acting as the personality of one of their headmates, they call this "fronting"

Related to Otherkin, Multiple Systems, and Tumblr social justice activist

I was so out of it I blacked out and one of my headmates took over and drove the car home.

HeadMate by psuedon April 7, 2013

headmaster

headmaster, n.

(1) the principal of a school or similar educational institution

(2) someone who is really good at oral sex

I got sent to the headmaster.

headmaster by IKEA May 12, 2004

Headmaster

head·mas·ter
/ˌhedˈmastər/
noun
(especially in private schools) the man in charge of a school; the principal.

The headmaster appears to have everything under control.

Headmaster by kaosmoker September 30, 2018

headmaster's duty 

The act of soliciting for the purposes of prostitution, i.e. a girl "working" in a bar, usually with unnecessarily revealing skirts and tops.

Has its origins in South London; etymology rumoured to be an oft-absent headteacher caught soliciting in the late 1970s. In order to avoid direct reference, the claim that he was doing his 'duty' evolved into 'headmaster's duty'.

I think she's probably up for a bit of headmaster's duty

headmaster's duty by londoncalling77 May 13, 2009

Headwatered 

The act of getting ripped off when buying a kayak you suspect is good but is in fact is a made in China piece of garbage.

My kayak cracked, I got Headwatered!

Headwatered by kayakfishing4life August 2, 2019