The term as used by the Witnesses is inappropriate. The thing is that the Witnesses try to make "Apostate" a special term that carries a significance that the word simply does not mean.
I have found that the Org needs to 'label' everyone (incorrectly) - both within and outside of It.
eg - PIONEER - lol, defintion? One who ventures into unknown or unclaimed territory to settle. One who opens up new areas of thought.......!