Here's what rhymes with firstborn.
born borne torn barn darn porn tarn corn worn horn warn yarn adorn morn mourn thorn shorn forborne lorn scorn sworn forlorn unborn reborn firstborn outworn stillborn lowborn waterborne forewarn peppercorn timeworn unworn sweetcorn careworn forsworn lovelorn foresworn unicorn Words that almost rhyme with firstborn
arm charm dorm form farm warm harm storm norm forme perform alarm forearm psalm swarm disarm deform firearm rearm reform inform outperform preform underarm yardarm overarm rewarm conform lukewarm thunderstorm nonfarm vermiform schoolmarm uniform transform fusiform cruciform multiform misinform chloroform cuneiform nonuniform on don dawn bon pawn aan bonne awn john upon non drawn gone von con lawn yon hon wan baton fawn han schon spawn yawn khan sawn sonne vpon brawn prawn faun gnawn thereon salon swan yuan fagon npon operon begone chaperon chiffon pecan tenon hereon predawn autobahn outdrawn withdrawn thereupon foregone whereon echelon exon redrawn forgone hereupon overdrawn aileron mastodon heptagon lasagne methadon undergone whereupon polygon automaton denouement pantheon positron octagon paragon pentagon amazon antiphon epsilon tarragon woebegone leprechaun neocon trimaran upsilon frogspawn lexicon hexagon marathon carillon cordovan emoticon phenomenon rapprochement pantechnicon