Source: Comment under: http://linuxlock.blogspot...icting-linux-desktop.html
"Non-free is relatively unambiguous: it means you can't modify it and you can't fix it when it breaks."
What an odd statement...perhaps as a specific label, you may be correct; when you are surrounded by people involved with FOSS, you are correct, by the grace of context and predisposition towards a specific meaning. Even Stallman, however, recognized that there is considerable ambiguity in the term "free" vs. "Non-free". Where do you think "Think free as in free speech, not free beer" came from? In fact, much of his influence comes specifically from his quest to differentiate between the two meanings of "free".
I read this and wonder how "non-free" with no context may be interpreted; I have paid for shareware to whose source I was granted access. That was "non-free", because I paid. I have not paid to use drivers distributed and developed by ATI whose source was a constant mystery. The ATI drivers are "freeware" that is not "Free Software (or open source)", while the other program was "Shareware" that was "Free (or open source)".
Of course, your definition of "Free" may also change depending on what organization you are following. After all, each of GPL, BSD, MPL, and FOSS, just to name a few, have slightly different viewpoints. Some give you source, but don't allow you to fork the source, or distribute the code you tweak. Some allow you to everything.
Narrowing your definition of a word that is ambiguous by definition to a single meaning is tantamount to starting a religious war. You may want to be careful with those kinds of statements. Context will define many aspects of "Free".