Boasts rhymes with:
coast's, coasts, ghosts, host's, hosts, jostes, post's, posts, roasts, toasts
Boasts sounds like:
backdates, backseats, backsides, backstage, backstitch, backstitches, backwoods, baghdad's, baskets, bassists, beachheads, beasts, beckwith's, beefsteak, begets, bequests, besides, best's, bestows, bestwick, bezdek, bigots, biscuits, bisuteki, bisuteki's, bobcats, boosts, boschwitz, bostic, bostick, bostock, bostwick, bouquets, boycotts, buckets, bustos, busts