Strengthen rhymes with:
lengthen, lengthen, anthon, blethen, bothun, brethen, cauthen, cauthon, cawthon, donathan, dothan, earthen, elizabethan, ethan, johnathan, johnathon, jonathan, jonathon, jonothan, kathan, lathan, lathon, laythan, lecithin, lengthen, leviathan, louthan, mathan, mcclenathan, mcglothen, mcglothin, mckeithan, mckeithen, mckethan, midthun, mithun, mothon, nathan, pathan, ramthun, snethen, swaminathan, trefethen, trevathan, warthen, wathen, witthuhn, worthen