How do Jehovah's Witnesses define "active" membership?

Only thing I'd add is that it's also based on meeting attendance. A witness that attends meetins regularly but doesn't really preach can still be considered active. "Inactive" is usually people who stop attending for a while (but haven't "disassociated themselves" per the article above.

Being an active witness involves doing the work that god has commanded of us. Matthew chapter 28 verse 19 says "go, therefore, and make disciples of peoples of all the nations, baptizing them in the name of the father and the son and the holy spirit"

So from this we display the model Jesus left for us. We take after him in the way we minister and teach. We witness or try to teach people about Jehovah god, his qualities, and his purpose for the earth and those on it. We usually do this door to door, but we also have public arrangements where people can approach and learn. We also witness informally to friends and family. What I am doing right now is considered witnessing.

This isn't the only factor. To be considered active you also have to attend the meetings. That command is found at Hebrews 10:25. It says there "Not forsaking our meeting together, as some have the custom, but encouraging one another, and all the more so as you see the day drawing near."

**EDIT:**Ok so I did some researching and dug out an article that is close. I have already defined an active member, but I found this which distinguish's the difference between an inactive and dissociated member. It clarifies what is considered to be inactive. Sorry in advance for the copy and paste. I will look for a copy of this on the site so I can paraphrase it and give a link.

My son, who was baptized as a teenager, is now married and has a family. Because of the pressure of earning a living he has cooled off spiritually and does not associate with the congregation. Should he be viewed as a “disassociated” person?

There is nothing in your description that would require such a viewpoint. The question may have arisen because of misunderstanding what it means to be viewed as “disassociated.”

The Watchtower of September 15, 1981, page 23, showed that there is a difference between (a) a Christian who becomes spiritually weak and inactive, and (b) a person who clearly renounces his being one of Jehovah’s Witnesses, leading the congregation elders to announce that he has “disassociated” himself. It seems that your son fits the first description.

The Watchtower mentioned that some Christians become weak in faith and spirituality. This occurred also in the first century. (Romans 14:1, 2; 1 Corinthians 11:30) It does not mean that they have ceased to be Christians. Even if they become so weak that they no longer share the “good news” with others and stop attending meetings, and they are not bringing reproach on the Christian congregation, they are still to be regarded as our spiritual brothers and sisters. We should want to help them lovingly, following the apostle Paul’s counsel: “We exhort you, brothers, admonish the disorderly, speak consolingly to the depressed souls, support the weak, be long-suffering toward all.” While the elders often take the lead in this, it is to be noted that this counsel was directed to all “the congregation of the Thessalonians.” (1 Thessalonians 1:1; 5:14) So the elders and others might offer loving help and encouragement, having in mind the advice: “Straighten up the hands that hang down and the enfeebled knees, and keep making straight paths for your feet, that what is lame may not be put out of joint, but rather that it may be healed.”—Hebrews 12:12, 13; Revelation 3:1-3.

It is quite a different matter with a former Christian who is “disassociated.” This designation is applied basically in two situations:

First, though it is uncommon, a person might decide that he absolutely no longer wants to be a Witness. We do not mean a person such as is described above, a spiritually weak or discouraged Christian who may express some doubts. Rather, we mean someone who resolutely declares that he absolutely is no longer one of Jehovah’s Witnesses. Since in the past he voluntarily became a baptized member of the congregation, it would now be proper for him to inform the congregation that he is ending this relationship. It would be best if he did this in a brief letter to the elders, but even if he unequivocally states orally that he is renouncing his standing as a Witness, the elders can deal with the matter.—1 John 2:19.

The second situation involves a person who renounces his standing in the congregation by joining a secular organization whose purpose is contrary to counsel such as that found at Isaiah 2:4, where we read concerning God’s servants: “They will have to beat their swords into plowshares and their spears into pruning shears. Nation will not lift up sword against nation, neither will they learn war anymore.” Also, as stated at John 17:16, “they are no part of the world, just as I [Jesus] am no part of the world.”—Compare Revelation 19:17-21. In either of these two situations, the person by word and/or actions has clearly terminated his status as one of Jehovah’s Witnesses, disassociating himself. Hence, the elders will announce briefly to the congregation that this individual has disassociated himself. Those in the congregation will accept the person’s decision and thereafter will view him as a former brother with whom they would not fellowship, in harmony with what we read at 1 Corinthians 5:11 and 2 John 9-11.

As can be appreciated, the spiritually weak and inactive son about whom the question was asked has not become a “disassociated” person in either of these two senses and no such announcement has been made in the congregation. So it still may be possible to aid him in the spirit of Romans 15:1: “We, though, who are strong ought to bear the weaknesses of those not strong.”—See also Isaiah 35:3. **

Taken from the 1982 watchtower on the topic of "disassociated person different from an inactive one"

Also I am an active Jehovah's witness. If anyone would like more information you can ask me or you can request information or a bible study from here JW.org If you look under the section Ministry it sheds some more light on what we do and why. The request info is on the bottom right of the website under contact us.

The definition of an inactive JW is that they are not active in their primary commission, which is of course the preaching of the good news of God's Kingdom. [Note: This refers specifically to preaching to non-Witnesses, whether in door-to-door "field service" or by some other method. This activity is structured, and time spent is recorded, reported, and compiled.] To my knowledge, this is the case if a Witness does not engage in preaching for a whole calendar month, but extenuating circumstances can be taken into account with the elderly and infirm being able to report much smaller intervals of activity. If a person is inactive they remain classified as this for three months following until they show that they are once again active in the service. Having said this inactivity is can also be accompanied by non attendance of meetings etc, but the primary definition is due to not being involved in preaching which in itself is a condition of "membership".

The difference between an active and inactive member can involve the duties that they are able to perform in the congregation as only those in good standing may be involved in some teaching assignments in the congregation (what would be the point of someone telling others to preach when they themselves do not?). Also persons that become inactive will be given extra attention to try and find the reason for inactivity and help them to return to service.

The count of members published per country every year includes only "active" members.