Newborn rhymes with:
colborn, colborne, deerborne, sonneborn, acorn, bralorne, capricorn, colborn, colborne, deerborne, eichorn, hagadorn, halliciforn, hathorn, hawthorne, heckendorn, kempthorne, langhorn, langhorne, leghorn, silverthorn, silverthorne, sonneborn
Newborn sounds like:
neoprene, nephron, new-bern, newbern, newburn, nonfarm, novopharm, nvryan