Transhuman is a term that refers to an intermediary form between the Human and the Posthuman.
The etymology of the term "transhuman" goes back to futurist philosopher FM-2030, formerly known as F. M. Esfandiary, who, while teaching new concepts of the human at New School University in 1966, introduced it as shorthand for "transitional human." Calling transhumans the "earliest manifestation of new evolutionary beings," FM argued that signs of transhumanity included protheses, Plastic surgery, intensive use of telecommunications, a Cosmopolitan outlook and a globetrotting lifestyle, Androgyny, mediated reproduction (such as In vitro fertilisation), absence of religious beliefs, and a rejection of traditional family values.
A transhumanist, on the other hand, is simply someone who advocates Transhumanism, an Emergent philosophy analysing or favouring the use of science and technology to overcome human limitations and improve the Human condition.
It is a common error for some social commentators to think and say that transhumanists "claim to be transhuman" or "call themselves transhuman." However, adopting a philosophy which says that someday everyone ought to have the chance to overcome their limitations is not to say that one is better or somehow currently "more evolved" than one’s fellow humans.