Here's what rhymes with firenew.
new knew mu nu moo gnu to who you do two too due du u coup qu shoe zu anew dew lieu renew shew su sue tu vous chew deux fu lu rue zoo bu hu ju jus ku loo peu pu seu shu sou vu woo yew yu boo chou chu coo cou doo ewe feu gu mieux ru shou thu tue vou wou wu goo mew pooh redo poo shoo roux thew whew into through few true view blue review drew grew que crew threw blew flew q canoe clue cue glue hue queue undue cu ensue flue slew stew undo adieu ado brew flu pew piu thru fue hew shrew tzu vnto vue clew zebu slue phew achoo revenue hitherto pursue screw avenue bamboo accrue retinue taboo untrue skew tattoo beaucoup eschew outdo revue shampoo sinew sprue imbue strew ballyhoo halloo honeydew spew valuer endue foreknew indue kazoo muumuu wazoo booboo regrew residue withdrew debut rendezvous subdue caribou jusqu overdue kangaroo askew outgrew overdo fondue marabou peekaboo bestrew overshoe prevue atishoo interview overview construe overthrew cockatoo hullabaloo bugaboo buckaroo overflew superglue overdrew overgrew barbecue barbeque misconstrue