Dude if you want an argument come over here...
I agree it's a vague term, but then do we really want to get into semantics and pedantry?
You could define it with a time line (say pre 1800) or materials and say no, glass, carbon metal etc.
I think you are presumtious to say no primititve bows had stiff handles.
If a neolithic bowyer found a gorgeous stave that just happened to have a big gnarly knot in the middle he'd have left it stiff.
I think it's patronising to think that 'primitive' man had neither the artistry, imagination, curiousity or humour to make odd character bows.
I'm not saying he did, but curiosity and humour are surely two on mans enduring and endearing traits.
Now who's going to help me down off this high horse?
Del