Bunting (n.1)
light woolen stuff loosely woven, flag-material," 1742, of uncertain origin; perhaps from a dialectal survival of Middle English bonting "sifting," verbal noun from bonten "to sift," because cloth was used for sifting grain. The Middle English verb is via Old French, from Vulgar Latin bonitare "to make good," from Latin bonus "good"

Source : Etymology online

Note: The Online Etymology Dictionary maintains a free-access list of the origins of thousands of English words, a significant proportion of which are unknown