Underline rhymes with:
borderline, borderline, casterline, dealerline, eberlein, enterline, esterline, heberlein, timberline, adeline, airline, alkaline, anticline, apolline, arline, arlyne, ashline, axline, baseline, berkline, bistline, bloodline, boehnlein, borderline, brookline, byerlein, byline, capitoline, caroline, casterline, coastline, coraline, crystalline, darline, dateline, deadline, dealerline, dragline, eberlein, econoline, emeline, emmeline, enterline, esterline, etheline, evangeline, feline, friedline, frontline, goeglein, gorsline, graveline, guideline, hainline, hairline, haneline, hardline, hartline, headline, heberlein, heinlein, hemline, henline, heublein, hineline, hotline, josceline, joscelyne, karline, karoline, kathline, kichline, lifeline, mainline, midline, moneyline, multiline, nightline, nonalign, online, outline, pipeline, punchline, roseline, sharline, shoreline, sideline, skyline, smithkline, stanline, stecklein, stoecklein, storyline, strandline, streamline, tagline, timberline, trendline, trunkline, waistline, wendeline, wickline, wireline