I have a large font collection, which I decided to sort according to licensing terms. While trying to learning more about font licensing, I came to know the term "Non-Commercial Free Usage" is somehow ambiguious. What is the exact meaning of this license with respect to fonts ?
Free to use for non-commercial purposes. Not really certain what's ambiguous about the term. It's basically the same as "free for personal use".
If you profit in any way by the usage of the font, it would be outside the usage permitted. You can't use the font for any client projects or any advertising. If there's any connection, whatsoever, to making income with a design, the font usage is not allowed.
I am not now, and have never been an attorney. This is not intended as legal advice.