Surely, one might say, this is not so. For instance, is it really so difficult to define determinism? It seems almost obvious on its face, but as it turns out, determinism is notoriously difficult to define. Take, for instance, causal determinism, which the Stanford Encyclopedia of Philosophy defines thusly (emphasis original):
The world is governed by (or is under the sway of) determinism if and only if, given a specified way things are at a time t, the way things go thereafter is fixed as a matter of natural law.
The author, philosopher Carl Hoefer, dutifully recognizes that this definition is vague and largely unhelpful until such time that its italicized phrases should be properly defined. However, I have found, both with lay and educated persons, that few if any have well-developed notions of those component terms, and, when they claim to, their accounts are either internally incoherent, mutually incompatible, or else conflict with popular or otherwise attractive accounts of the same terms used in different contexts. This situation makes it difficult to communicate effectively when we permit the use of the word determinism.
The same sort of trouble applies, to I dare say an even greater degree, to discussions about free will, which is so poorly defined in most contexts as to render it utterly useless without first explicitly elucidating one's own account in advance of each employment. However, others are not often prepared, in my experience, to accept such stipulative definitions, and so it becomes necessary instead to solicit an account from one's partner in conversation. This in turn is only possible if that person has already spent some time developing such a definition, or is willing and able to do so on demand. Clearly, we should expect few to meet that criterion. For those who do, we must, at a minimum, acknowledge that it is a serious inconvenience to lay down precise stipulative definitions before every conversation regarding free will or determinism. How much worse if, after spending the time to do so, it turns out that the proposed definitions are incoherent or otherwise disagreeable!
Besides that, we really have no need to provide content to a word or phrase which lacks it. We are instead perfectly able to simply acknowledge that they lack content, and accordingly abandon them. These terms, apparently as a rule, invite misunderstanding and tension where they do not require significant commitments of time and energy in defining, and I therefore feel inclined to avoid them altogether. As a consequence of my decision, I must likewise avoid discussion of compatibilism or libertarianism, since those terms are defined based on the concepts of free will and determinism. To clarify, I don't mean to suggest that these terms cannot be endowed with precise and meaningful conceptual content, but only that to do so seems unnecessary and, in light of the serious cost of convenience for defining them, woefully inefficient. As metaethical philosopher Richard Double once wrote, regarding whether or not moral claims bear truth, "The inability of 'I am thinking of the largest integer' to be true does not provide reason for thinking the statement is a disguised exhortation, command, or wish." I find relevance in his observation likewise to the present discussion; for, if free will and determinism lack meaning on some account does not somehow compel us to provide them with such. I contend that, in order to encourage limpidity and efficiency of communication, we ought to leave them unapologetically behind.
Let us keep in mind, though, that restricting our language does not necessarily prevent us from communicating a given idea. Unless one of the four terms in question is a primitive term with a meaning which cannot be communicated alternatively, then whatever content lies behind them all may be discussed using a reduced vocabulary. This is precisely what I would like to do from now on, avoiding the four problematic terms, and instead discussing directly whatever objects we happen to find of interest in a particular context. So, for example, one might ask whether the God of Calvinist theology is morally praiseworthy or blameworthy. A dispute on that subject could take the following form: a non-Calvinist argues that Calvinism teaches determinism, which cannot be true since human beings have libertarian free will; a Calvinist in response argues for compatibilism. However, whether or not compatibilism versus libertarianism is true is only interesting in that context insofar as it relates to the topic of immediate interest, which regards the moral status of the Calvinistic God. It is entirely possible to discuss that topic without mentioning libertarianism, compatibilism, etc. Indeed, I suggest that it is easier and relatively painless to avoid those terms.
Nevertheless, some may insist that their terms are indispensable. If so, then I believe it is possible to show them that they are either mistaken, or else they are taking the terms to have primitive content. If the latter is true, then the conversation is doomed unless all parties already share the concepts in question, in which case it remains only to point out that one lacks such concepts. For instance, I myself only understand determinism and free will to the extent that they can be defined using component terms; so, I will be unable to communicate effectively with anyone for whom the conceptual content behind their own use of the terms is primitive. Otherwise the terms are not primitive, which is to say that their underlying conceptual content is alternatively communicable. So we are free to opt for that alternative; indeed, I believe we should do just that, for the reasons given thus far.
Yet this is not to require that we must never make mention of the terms, but only that we do so in reference strictly to the terms themselves, and their status as objects of philosophical positions. So, in this document for example, I have extensively discussed free will as a term which may be employed in the English language, and this kind of use I fully appreciate. Naturally, if we do wish to avoid the terms as they are typically used, that is, as representative of some supposed philosophical concepts, then it will not do to simply ignore them when a person employs one or more of them in the course of a conversation. Rather, we must patiently and politely explain to that person why we cannot permit their continued use, and suggest alternatives.
Finally, we may observe that this policy of avoidance is primarily motivated by conversations with non-specialists. I freely confess that I have not had much occasion to discuss free will and determinism with professional philosophers who have spent time developing those terms. However, since the vast majority of persons are not professional philosophers, and even among philosophers we should expect few to specialize in free will or determinism, I do not anticipate this seriously impeding my proposed conversational strategies. If I happen to discover in the near future that resisting the problematic terminology of free will and determinism in this way results in unforeseen difficulties outweighing those which accompany the terms themselves, then I may revise my plan of action, and make less limited use of that language. However, in the mean time, I very much hope to avoid doing so, and I hereby encourage others to follow my example.
 Although the statement "God is omnipotent and omniscient," call it A, does not appear in the deductive argument, of those premises which do appear, call them P1,P2,...,P7, the rhetorical points discussed beforehand may be taken to defend the heretofore unspecified statement A → P1∧P2∧...∧P7 from which A → B follows, where B is the argument's conclusion, that God completely controls the choices of all agents.
 Hoefer, Carl. "Causal Determinism," Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/determinism-causal
 Double, Richard. Metaethical Subjectivism (2006), ISBN 0-7546-5417-6, p36. http://books.google.com/books?id=M3PMl1vVN6EC