Transmedicalism

The belief that one needs to have gender identity disorder/gender dysphoria to be transgender.

Also the belief that one has to meet society's expectations of appearance and behaviour of their preferred gender in order to be considered transgender.
Truscum people usually don't think that transgenderism/transsexualism (two terms that they consider to be strongly attached to one another) is normal human behaviour,but rather applies to a small minority of people who have an innate or acquired psychiatric disorder. They also typically think of anyone who claims they're trans without meeting those criteria as a "transtrender", ie. someone who claims to be trans for the sake of being seen as "different", "special" or "a rebel".

the belief that you are only transgender if you experience dysphoria or want to have gender confirmation surgery

Someone who believes that you don't need dysphoria to be transgender, as it was proved by a lot of medical research and by science. Transmedics are also pro non-binary and pro non-dysphoric, and wants to help and love all our trans siblings !