Grimacing rhymes with:
promising, buttressing, canvassing, embarrassing, encompassing, focusing, harnessing, menacing, necklacing, practicing, promising, purchasing, refocusing, repurchasing, resurfacing, surfacing, witnessing
promising, buttressing, canvassing, embarrassing, encompassing, focusing, harnessing, menacing, necklacing, practicing, promising, purchasing, refocusing, repurchasing, resurfacing, surfacing, witnessing