1. One of the German princes and cities that protested against the decision of the second Diet of Speyer (1529) to enforce the Edict of Worms (1521) and deny toleration to Lutherans. This is the original meaning and the origin of the term.
2. A Christian or Christian organization whose faith and practice are founded on the principles of the Reformation, especially the teaching of Sola Gratia/Solus Christus/Sola Fide and often also embracing accountability and the praxis of Sola Scriptura.
1. Non-Protestant. Originally, it simply referred to a group of German princes protesting the forbidding of Lutherans to worship in certain Catholic areas. It had nothing to do with the Pope or the Catholic Denomination, it was about the Diet of Speyer. But, in time, it became a term of derision by some Catholics to refer to those who, IN THE OPINION OF THOSE CATHOLICS, were "protesting" the absolute, unaccountability of the Pope. It typically was not extended to Eastern Orthodox Christians and organizations. For some, it still has this deragatory, condemning meaning and is still a Catholic term of derision, although this is now rare.
2. Protestant. Those Christians and Christian organizations that identifiied themselves with neither the RCC or EO, but who embraced Sola Gratia/Solus Christus/Sola Fide originally called themselves "Evangelicals." For a time, they resisted the term of derision, not only because it was intented to be deflamatory but because it was inaccurate - they were not about "protesting" anything but in proclaiming the Gospel as they understood such. But, in time, the term lost its derivise quality and simply became a very sloppy term for Lutherans, Anglicans and Calvinists as a group. In time, these Christians themselves began to use the term as a generic label for the commonality of this group - especially vis-a-vis Sola Gratia/Solus Christus/Sola Fide. This was not only true for "Protestant" but also for "Lutheran" and later "Methodist" and "Baptist" and many more ( originally terms of derision that came into such common use and lost that negativity so that those in those groups began embracing the label).
1. A "Protestant" is not one who fundamentally "protests." This is simply an inaccurate usage of the term. The only "protest" involved was to the Diet of Speyer in 1529. He/she is one who embraces what they regard as biblical Christianity and the defining concept of Sola Gratia/Solus Christus/Sola Fide and likely the epistemological praxis of Sola Scriptura. I'm Protestant, but I don't "protest" the Catholic Church - I hold it in very high regard and consider it valid.
2. A "Protestant" is not simply a Christian who is not officially registered in a congregation legally affiliated with the Catholic Denomination. Such would mean that Orthodox Christians, Mormons, Christian Scientist, etc. would be "Protestant" as they would deny (correctly).
3. While undeniably Luther, Calvin and others were "against" a few things in the Catholic Denomination of their day at some points AND the RCC was "against" them to the EXACT same degree on the EXACT same issues. Thus, Luther and the RCC were BOTH "protestant" (if such is defined as "in disagreement") to the EXACT same degree and on the EXACT same issues. But note that the RCC excommunicated Luther - not the other way around.
4. I take no automatic offense at the labels "Lutheran" or "Protestant." Indeed, I embrace and use them - even aware of their "history." Those registered with the LDS are typically no longer taking offense at "Mormon" (indeed, many of them have embraced it).
5. I do think the term should be understood and used correctly. As such, no offense will be taken (or implied) and nothing other will be meant.