Redoubt rhymes with:
doubt, doutt, about, all-out, bout, clout, crout, devout, doubt, doutt, drought, flout, fout, gout, grout, hout, how-about, kraut, krout, lout, out, pout, prout, raut, rout, routt, scout, shout, shrout, snout, spout, sprout, stake-out, stout, stoute, strout, throughout, thuot, tout, trout, troutt, without
Redoubt sounds like:
ratified, redbud, redpath, ridpath