The duty of Jihad has to be defined accurately, but also in a way that can easily be grasped by auditors, so that it does not exclude, but clearly includes, all of the current instruments that Muslims employ to further Jihad.
The initial smokescreen, or deception, offered both by Muslims and by such non-Muslim apologists as Karen Armstrong and John Esposito, was to suggest, or even insist, that the very recent, and most secondary, definition of "Jihad," formulated primarily by some "reforming" Muslims in the last century (at a time when Muslims were weak, and in apparent disarray), was the widely-accepted one. But this has been impossible to sustain, given the widespread use by Muslims themselves – now copiously quoted at such sites as MEMRI, and in newspaper and radio and television accounts – of the real meaning of Jihad.
And what is that meaning? To repeat: Jihad is a duty, incumbent on all Muslims, to strive to remove all obstacles to the spread, and then the dominance, of Islam, all over the world. In the earliest days of Islam, those obstacles would be military in nature: Muslims invade a land possessed by non-Muslims, fight to conquer them, and then to impose Muslim rule over them, and to offer them the choice of death, conversion, or life as dhimmis under such rule. But in the modern world, when non-Muslims still possess overwhelming military superiority, it is not "qitaal" or combat in the traditional sense that is the main instrument of Jihad. Rather, even when it comes to the use of violence, the preferred method is the kind of attack on non-military targets, designed to instill terror, that we have no difficulty calling terrorism. Such attacks -- on airplanes, on busses, on schools, on subways, on office-buildings, on hospitals – are explained away or justified by Muslims, as perfectly acceptable variants on traditional "qitaal" or combat. And since Infidels have more powerful armies, terrorism is seen as merely a way of equalizing things, and not itself morally unacceptable. Still other Muslims, while feigning to denounce a vague "terrorism," always leave open, in their failure to define what constitutes "innocents" or "civilians," the acceptance of terrorism as a method. And indeed those very infrequent and pro-forma "denunciations" no longer fool as many as they once did, so often have those loopholes been pointed out – and too many Muslims among those denouncing terrorism have been found to support it in one way or another.
But the definition of Jihad must be ample enough to include all the other instruments, aside from qitaal or terrorism, that are used with such effectiveness today. These instruments of Jihad include the deployment of the Money Weapon, campaigns of Da'wa (the Call To Islam, which means the attempt to convert as many susceptible Infidels, among the economically and psychically marginal, as possible), and demographic conquest, which consists of both the deliberate, and the non-deliberate (but just as effective and dangerous) overbreeding of Muslims in Infidel lands. That increase in numbers leads, as Boumedienne of Algeria said in 1974 at the U.N., to a conquest "through the wombs of Muslim women." The generous benefits of Infidel nation-states allows Muslim women not to work (though non-Muslim women do), to have large families, and to take full advantage, and then some, of all the benefits – free and excellent medical care, free education, free or heavily-subsidized housing, and generous family allowances – that appear tailor-made for the large Muslim families who are busy, in their own way, increasing inexorably the Muslim presence, and therefore perceived and real power, all over the Bilad al-kufr, the Lands of the Infidels. This is accompanied by continued large-scale immigration of Muslims. And instead of halting this immigration and constructing policies designed to limit the size of Muslim families, or at least not to be so generous with support, and even to promote policies that may make it more difficult, or at least not quite so easy, to conduct Muslim life in a non-Muslim environment, the Western world so far, now that it recognizes a problem, appears incapable of soberly drawing up the measures that it has every right to employ to protect its own legal and political institutions, the conduct of art and science, and the development of individual liberties so threatened by the collectivism of that Total Belief-System that some, too easily call a "religion," which is to say – Islam.
So, if you are asked to provide an intelligible and comprehensive definition of the word "Jihad" provide this:
Jihad is the duty incumbent upon all Muslims, to participate, sometimes directly and sometimes indirectly, to engage in the "struggle" (which is what "Jihad" means) to remove all obstacles to the spread, and then to the dominance, of Islam. It can take the form of combat, or qitaal. It can take the form of terrorism, It can take the form of the Money Weapon, which Saudi Arabia alone has supplied, or distributed, to the troubling tune of nearly one hundred billion dollars over the past few decades, to support mosques, madrasas, armies of Western hirelings, and every sort of pro-Islam propaganda, from textbooks in the schools, to those interfaith-healing racketeers who ply their smiling trade, some of them naïve, and some of them knowing exactly what they are doing. It can take the form of carefully-targeted campaigns of Da'wa, especially in prisons or among the psychically marginal. These people go off on their Spiritual Searches and finally allow their personal mental Greyhound to stop at the station marked Islam, where they got off that bus, never to get on again.
And finally there is demographic conquest, which has to be halted and then reversed, through measures that are perfectly acceptable ethically and morally, and that, in a rightly-ordered world, and among Infidels less willfully determined not to recognize the dangers that are daily mounting, would have been undertaken long ago.