Is 'Non-Catholic Non-Orthodox Modern Western Denomination' an ok definition of Protestant? One meaning of the term "Protestant" is "a church drawing its roots from the Reformation and the denominations of the Reformers in particular".  I have also seen the term extensively used to mean "a modern non-Catholic non-Orthodox western denomination" with 'modern' meaning dating back no earlier than roughly the time of the Reformation and 'western' generally meaning embracing western scholasticism and enlightenment thinking in general.  I have recently been told that the latter meaning is "just wrong".  Is the latter definition 'wrong' in some fundamental way and what reasons are there to use or avoid using it?  If it is wrong, what term (not "modern non-Catholic non-Orthodox western denomination" please, that's just way too long) would be better for this broader usage?
Your question is a good one, but it is slightly misguided.  You are seeking a precise definition for a term which does not have one.  The word Protestant can mean different things depending on the context in which it is used.  When used in a historical context, it may be used to strictly refer to those involved in the Reformation and to the churches that they directly founded.  However, it is also perfectly legitimate and acceptable to use the term Protestant to refer to any Christians or Churches that espouse the same principles as the original Protestant reformers.  

The biggest commonality among Protestants is that they denounce the universal authority of the Papacy.  Beyond that, the term Protestant is much like the term Christian.  It essentially applies to anyone who chooses to apply it to themselves.  In that sense, I do think that you were using the term appropriately, as long as you only intended it in a loose way.  It would be wrong to correct someone's use of the term by suggesting that the term can only legitimately be used in a historically precise way.