While English is the de facto language for technical documentation, it’s a headache when it comes to using the two key words of the free software philosophy: Free and non-free. I mean, to explain what free software is all about, we should also explain what we mean by “free”.
This is so true, that English-speaking people had to borrow a word from another language to work around this ambiguity. Now the “Free as in Freedom, not as free beer” issue is resolved by using a single word: Libre. But, what’s the antonym of Libre? Non-libre? No, it’s non-free or proprietary! (non-libre is seldom used); what a muddle.
Also, both “non-free” and “proprietary” miss the point, just like open-source does in a similar sense; on one hand, “non-free” means that something is not free (yes, I’m a genius!), so we’re back to the starting point, as we have to explain what we mean by “non-free” (a non-gratis-bear or a non-libre-person?) and “non-free” is not an strong term; on the other hand, “proprietary” means that something has one or more owners, that’s it. We need an strong, offending term.
What about “Freedom-depriving software”? It’s the perfect term to refer to software like Microsoft’s. It’s not ambiguous in English, it’s simple and it’s offending (just what they deserve). We can say “Windows is a Freedom-depriving software” and everyday computer users will get what we mean.
PS: English already has a word that perfectly defines the contrary of “Free as in Freedom”: Privative. But people may argue that this is the worst solution because “privative” is an unusual word… And that would be a valid point.