If you do not share the "beliefs unique to Jehovah's Witnesses" then you can be disfellowshipped. In other words, even if you never utter a word about what you do believe, your actions might give away the fact that you do not share the "beliefs unique to Jehovah's Witnesses" and you would be considered an apostate.
*** w86 4/1 p. 31 Questions From Readers ***
Approved association with Jehovah’s Witnesses requires accepting the entire range of the true teachings of the Bible, including those Scriptural beliefs that are unique to Jehovah’s Witnesses.
The part about "true teachings of the Bible" and beliefs needing to have "Scriptural" backing is hogwash. The Bible does not address matters such as the length of a skirt, beards, moustaches, needing to drive 4-door cars, not going to college, but the WTS considers its "opinions" and "suggestions" on these matters to be critical to a person's survival at Armageddon™.
In other words, as soon as you no longer attend meetings or participate in field service, you are technically in apostate-land. The more you do that is frowned upon by JWs and the WTS, the further you are in apostate-land. You do not have to utter a word to anyone, because your actions are speaking for you.