Those that disagree with the WTS' teachings are by definition apostates. The following is from http://www.apologeticsindex.org/a67.html "An apostate is someone who abandons a previous loyalty (to a faith, movement, politcal party, etcetera).
Cult defenders such as Massimo Introvigne, J. Gordon Melton, Lonnie Kliever, et. al., attempt to discredit the testimomy of apostates.
However:
Recent and less recent NRM catastrophes help us realize that in every single case allegations by hostile outsiders and detractors have been closer to reality than any other accounts. Ever since the Jonestown tragedy, statements by ex-members turned out to be more accurate than those of apologists and NRM researchers. The reality revealed in the cases of People's Temple, Rajneesh International, Vajradhatu, the Nation of Yahweh, the Branch Davidians, the Faith Assembly, Aum Shinrykio, the Solar Temple, or Heaven's Gate is much more than unattractive; it is positively horrifying. In every case of NRM disasters over the past 50 years, starting with Krishna Venta (Beit-Hallahmi, 1993), we encounter a hidden world of madness and exploitation in a totalitarian, psychotic, group, whose reality is actually even worse than detractors' allegations." Also according to dictionaryreference.com
apostate
adj : not faithful to religion or party or cause n : a disloyal person who betrays or deserts his cause or religion or political party or friend etc. [syn: deserter, renegade, turncoat, recreant, ratter]
Hope this helps
FM