(This is still under construction).
Key points:
How they practice it
The effects on the JW
How their definition leads to unfair, unbiblical,
cruel consequences
The proper and biblical form of discipline
To "keep the congregation clean" the Jehovah's Witnesses have a practice called "disfellowshipping" (the rest of the religious world more commonly calls this "shunning"). Simply stated, if the JW organization determines by their religious court process that a baptized member is "wicked" - and the member can only appeal this decision once - then the member will be shunned by all JWs, everywhere. They are treated as though they do not exist. It is quite routine to hear of JW parents shunning their ex-JW children who live outside the home, and never seeing them again, even until their deathbed.
There are two special cases that regulate how much contact is allowed: JW family members who live in the same home and JW business associates. Close family may speak to the ex-JW but only on subjects for which the Watchtower Society holds no opinion. Since the Watchtower Society takes a stand on every possible issue that might be right or wrong, this means in practice that family members will only discuss the weather and the basic activities of daily living but nothing that might relate to spiritual, ethical, or religious matters. Similarly, JW business associates may converse with the ex-JW but it must be strictly limited to business matters.
The JW organization has rules on disfellowshipping for things you would expect such as immoral conduct and breaking the civil laws but tmembers can also be DFed for other things like taking a blood transfusion, for speaking to other JWs about disagreements or doubts with Watchtower teachings and practices.
Most new JWs follow policy and allow all non-JW relationships to expire but seek to get any non-JW family members to join. As a result, the typical JW has no social contacts outside of the "organization", i.e., the Watchtower Society. Their entire emotional and psychological support system is within the JW confines. So an ex-JW suddenly finds there is no one to turn to for emotional or psychological advice, no one who can listen with understanding and emphathy. Grandparents never see their grandchildren. Children will shun their ex-JW parent(s) and never communicate with them ever again. This sounds extraordinary, but it is really quite routine.
How their definition leads to unfair, unbiblical, cruel consequences.
The Watchtower normally requires that there be two eye-witnesses to the sin before action is taken. This has not always been their rule and at times would accept two eye-witnesses to two different but similar events or one eye-witness if the person was very reliable. If the accused person confesses and repents, the sin may be kept completely confidential. This may sound very fair but if the sin is child-molestation, it is not (see silent lambs).
There are inconsistencies with their application of their congregational cleanliness policy and the need for two eye-witnesses. If a JW sees another commit a sin, they are required to report it to the JW authorities (elders). For example, if a JW nurse learns that another JW has had a test for a sexually transmitted disease, this must be reported even though it may be breaking a local law or employer's regulation. If the JW does NOT report the sin, that person could be disfellowshipped for not reporting the sin. But if the JW does report the sin to the elders, and no other eye-witness comes forward, the accused may plead innocent and potentially accuse the witness of "slander", also a "disfellowshipping offense".
There have been occasions where a JW was an eye-witness to a serious crime committed by another JW and reported it. The crime was so serious that others were in danger of either physical harm or moral corruption. If the JW had not reported the sin, others would have been in danger and if another testifier eventually came forward, and it became known that a silent JW had hesitated to report the sin, the silent JW could be disfellowshipped. So the JW reported the sin. Since there was only one eye-witness, the elders did not act. Yet the witness was greatly concerned and worried about the safety of others and warned them. The accused JW then accused the innocent witness of "slander". Since the witness had already warned two other JWs, that was enough to meet the rule of "two eye-witnesses" and the innocent party who did right by reporting the sin was disfellowshipped while the guilty party continued to behave as before.
There have been other cases where the Watchtower Society published a rule that affected families in foreign countries. In some places it is (or was) illegal for JWs (or even Christians) to marry or illegal for persons to marry unless they joined the local religious/political group. So the Watchtower allowed couples to be married in the 'eyes of the religion'. In some places these couples could potentially get married but it might be very expensive or for some other reason prohibitive.
In a few cases where one spouse was a JW but the other was not, this became a problem. Even though the Watchtower Society had long recognized such unions, they changed their rule such that if there was any way to legalize the marriage, even at great cost, the couple must seek to do that or the JW spouse would be disfellowshipped. But some non-JW spouses felt that since the Watchtower had recognized the marriage before, there was no compelling reason to go to great expense and trouble to now legalize it. The result was that the JW-spouse, often a woman, was forced to leave the marriage even though there were children. She was not legally or religiously divorced, she got no financial support and could not remarry. Then a little over a year after the break-up of these marriages, the Watchtower changed its ruling and decided that the women did not need to leave their marriages but could go back and only those couples who were both needed to either legalize or live apart. . . . But what about the JW women that could now go back but the non-JW husbands had since remarried. The JW-women could no go back to their former lives and to their children.