In Jane’s world, a zinger can be a stripe of contrasting yarn, something that draws your attention to the cloth. For instance - cloth with shades of grey, wouldn’t draw your attention to it, and that’s fine if that’s what you want. If you want your cloth to be interesting - then add a stripe (or more) of red and notice how your eye is drawn to it and adds interest to your fabric. That’s a zinger. I don’t think you’ll find that word in with most weaving terminology - but it’s very much a “Jane” word!