Term idea: Idiosynth
Idiosynthing: The action of quickly adopting personality traits from others in such a way that it causes major, noticeable (to yourself or others) changes to your own personality, mannerisms, way of talking, etc. Often temporary, but can be permanent. Created with people with BPD and autism in mind, but can be used by anyone that feels like they experience it
Idiosynth:
The verb describing this action; to idiosynth
The noun to describe who you're masking with; an idiosynth
May also be shortened to "synthing" or "to synth." "Idios" for the noun form might be used as well, though unfortunately it's very close to the term "idiot" and may be misunderstood
Pronounced id-ee-oh-sinth or eed-ee-oh-sinth, either is fine
Example
Say that you as a person are typically a timid, self-deprecating person. You often avoid others and feel bad about the things you do. Most of your friends know this about you, and can recognize when you're feeling especially down, as you tend to isolate yourself.
Those friends invite you to a movie night, and your brain instantly connects with one of the characters in movie. They're incredibly charismatic, bubbly, friendly, and confident. While you watch the movie, part of you changes, and afterwards you find yourself talking more like that character, growing more confident in yourself, and becoming less timid. You put more time into being the first one to message your friends or invite them to things; you find yourself having less desire to be alone for a time.
A few weeks later, you've started shedding these traits and going back to your "usual self," as those self-deprecating thoughts creep back in and you find yourself taking more and more time to be alone. You've stopped engaging with that movie and the fandom around it, which has dried up your mind's immediate interest in that character, and you find yourself no longer acting the same way as them.
That's the kind of experience this term is describing: taking on traits that others have to the point where it completely changes how you act. It can make you meaner, kinder, shyer, more confident... The exact traits will change depending on the person you're synthing from, and they can be positive or negative.
Origin
From the Greek word ίδιος (idios), meaning one's self or belonging to one's self. This was chosen as idiosynthing is often a very personal thing that changes what might feel like your very being, often due to personality and identity confusion that comes with being ND
Synthing is a shortening of synthesizing, referring to the action of synthesizing different traits from people and taking them on yourself
The term is also similar to idiosyncrasy, or behaviors and thought patterns that are often unique to a person. This experience can change your idiosyncrasies to be those of another person, or may lead you to taking on others' in addition to your own
History
There's probably a few terms out there describing this, but I don't think I've found them yet. The closest I've gotten is constelic, which I do also identify with, but I wanted a term that had less ties to kin or alterhuman communities (which: it's not a kin term, but, still) and was more focused on the ND part of it. There's also the fact that this doesn't necessarily change how you identify so much as how you behave or express yourself, and what constitutes your personality rather than identity
As someone with BPD, autism, and DID, my brain often looks at fictional villain characters and "steals" traits from them, whether that means the way they talk, the way they move, the way they treat others, etc. This isn't something I can control and it's incredibly hard to stop once it starts- I usually have to wait it out and avoid that piece of media for a while. Sometimes getting back into it or being reminded of it will get my brain going again, but at that point it's typically a bit easier to control since I know what traits to expect to change. A lot of the time this can be a good thing, as it gives me a boost that helps me get things done, but most of the time for me these traits force me to work harder to be the kind person I want to be. I'll find myself being more sarcastic and sassy than usual, or darker and edgier, or giving into my depression more. It ranges a lot!
Moving on: while this was originally created with fictional characters in mind, it may also apply to people borrowing traits from real life people. For example, someone with BPD might synth as their FP (favorite person) for a time. People with autism may synth as their best friends, or celebrities they have a special interest in
This term is intended for ND people, but there are no other requirements. You don't have to have BPD or autism or DID, or anything similar. If your brain has a tendency to borrow traits from others for a while, which results in major changes to the way you yourself behave, talk, think, or interact with others, then congrats- the term is yours!
Restrictions
This term doesn't really have restrictions, but I do want to make some things clear:
This term is not an identity term per se, but rather a term like "masking." It's intended to describe something you do, not something you are. If you want though, you can probably use idiosynth as an identity
Due to the above, there currently is no flag. We may think about creating one later, but right now, we would actually prefer if there was no flag for this term.
This term is intended to be connected to the neurodivergent community, not necessarily the kin, alterhuman, etc communities. In short, "it's not an otherkin term" is what I'm trying to say. People in those communities are welcome to it, however!
This term doesn't inherently have to do with gender or orientation, but it may affect your gender presentation. As gender/etc is more part of your identity, we tried to avoid considering that as part of this term. However, if you still feel like the term fits you, then you're more than welcome to use it :)
Pretty sure that's all for now, I'll be sure to update this if I feel the need to add to it. Feel free to tag this account or @xgrskx if you want to share things about your experiences with idiosynths :3