Here's what rhymes with couteau.
o au oh owe aux bo doe dough po toe tow beau eau jo ow beaux cho dau eux oe doh no so know go though low show co blow grow pro row tho fo foe glow ho lo quo mo ro wo woe crow yo bio ceux faut goe hoe ko sew soe vo mow noe roe sho tuo yeux zo bro rho stow trow kapok whoa gateau kayo gateaux below ago flow slow snow throw audio fro chateau thro uno aglow dicho floe topos chateaux dunno throe chapeau sloe tarot turbot chapeaux pekoe borzoi schmo schmoe although radio plateau bestow hello patio nouveau polio propos tableau cameo escrow outgrow rodeo siglo tableaux plateaux trousseau oleo deathblow regrow bandeau matzoh fatso trousseaux resew ratio embryo studio undergo buffalo folio indigo stereo calico dynamo forego forgo vertigo aliquot apropos domino medico spatio adagio piccolo undertow foreknow overgrow microdot romeo tallyho overthrow overflow portico bungalow mistletoe afterglow oregano pompano politico presidio pistachio mustachio moustachio portfolio archipelago braggadocio pianissimo impresario generalissimo