undern nudern udnern dunern nduern dnuern unedrn nuedrn uendrn eundrn neudrn enudrn udenrn duenrn uednrn eudnrn deunrn edunrn ndeurn dneurn nedurn endurn denurn ednurn undren nudren udnren dunren nduren dnuren unrden nurden urnden runden nruden rnuden udrnen durnen urdnen rudnen drunen rdunen ndruen dnruen nrduen rnduen drnuen rdnuen unerdn nuerdn uenrdn eunrdn neurdn enurdn unredn nuredn urnedn runedn nruedn rnuedn uerndn eurndn urendn ruendn erundn reundn nerudn enrudn nreudn rneudn ernudn renudn udernn duernn uedrnn eudrnn deurnn edurnn udrenn durenn urdenn rudenn druenn rduenn uerdnn eurdnn urednn ruednn erudnn reudnn derunn edrunn dreunn rdeunn erdunn redunn nderun dnerun nedrun endrun denrun ednrun ndreun dnreun nrdeun rndeun drneun rdneun nerdun enrdun nredun rnedun erndun rendun dernun edrnun drenun rdenun erdnun rednun undenr nudenr udnenr dunenr nduenr dnuenr unednr nuednr uendnr eundnr neudnr enudnr udennr duennr uednnr eudnnr deunnr edunnr ndeunr dneunr nedunr endunr denunr ednunr undner nudner udnner dunner nduner dnuner unnder nunder unnder nunder nnuder nnuder udnner dunner undner nudner dnuner nduner ndnuer dnnuer nnduer nnduer dnnuer ndnuer unendr nuendr uenndr eunndr neundr enundr unnedr nunedr unnedr nunedr nnuedr nnuedr uenndr eunndr unendr nuendr enundr neundr nenudr ennudr nneudr nneudr ennudr nenudr udennr duennr uednnr eudnnr deunnr edunnr udnenr dunenr undenr nudenr dnuenr nduenr uendnr eundnr unednr nuednr enudnr neudnr denunr ednunr dneunr ndeunr endunr nedunr ndenur dnenur nednur endnur dennur ednnur ndneur dnneur nndeur nndeur dnneur ndneur nendur enndur nnedur nnedur enndur nendur dennur ednnur dnenur ndenur endnur nednur undrne nudrne udnrne dunrne ndurne dnurne unrdne nurdne urndne rundne nrudne rnudne udrnne durnne urdnne rudnne drunne rdunne ndrune dnrune nrdune rndune drnune rdnune undnre nudnre udnnre dunnre ndunre dnunre unndre nundre unndre nundre nnudre nnudre udnnre dunnre undnre nudnre dnunre ndunre ndnure dnnure nndure nndure dnnure ndnure unrnde nurnde urnnde runnde nrunde rnunde unnrde nunrde unnrde nunrde nnurde nnurde urnnde runnde unrnde nurnde rnunde nrunde nrnude rnnude nnrude nnrude rnnude nrnude udrnne durnne urdnne rudnne drunne rdunne udnrne dunrne undrne nudrne dnurne ndurne urndne rundne unrdne nurdne rnudne nrudne drnune rdnune dnrune ndrune rndune nrdune ndrnue dnrnue nrdnue rndnue drnnue rdnnue ndnrue dnnrue nndrue nndrue dnnrue ndnrue nrndue rnndue nnrdue nnrdue rnndue nrndue drnnue rdnnue dnrnue ndrnue rndnue nrdnue unernd nuernd uenrnd eunrnd neurnd enurnd unrend nurend urnend runend nruend rnuend uernnd eurnnd urennd ruennd erunnd reunnd nerund enrund nreund rneund ernund renund unenrd nuenrd uennrd eunnrd neunrd enunrd unnerd nunerd unnerd nunerd nnuerd nnuerd uennrd eunnrd unenrd nuenrd enunrd neunrd nenurd ennurd nneurd nneurd ennurd nenurd unrned nurned urnned runned nruned rnuned unnred nunred unnred nunred nnured nnured urnned runned unrned nurned rnuned nruned nrnued rnnued nnrued nnrued rnnued nrnued uernnd eurnnd urennd ruennd erunnd reunnd uenrnd eunrnd unernd nuernd enurnd neurnd urnend runend unrend nurend rnuend nruend ernund renund enrund nerund rneund nreund nernud enrnud nrenud rnenud ernnud rennud nenrud ennrud nnerud nnerud ennrud nenrud nrneud rnneud nnreud nnreud rnneud nrneud ernnud rennud enrnud nernud rnenud nrenud udernn duernn uedrnn eudrnn deurnn edurnn udrenn durenn urdenn rudenn druenn rduenn uerdnn eurdnn urednn ruednn erudnn reudnn derunn edrunn dreunn rdeunn erdunn redunn udenrn duenrn uednrn eudnrn deunrn edunrn udnern dunern undern nudern dnuern nduern uendrn eundrn unedrn nuedrn enudrn neudrn denurn ednurn dneurn ndeurn endurn nedurn udrnen durnen urdnen rudnen drunen rdunen udnren dunren undren nudren dnuren nduren urnden runden unrden nurden rnuden nruden drnuen rdnuen dnruen ndruen rnduen nrduen uerndn eurndn urendn ruendn erundn reundn uenrdn eunrdn unerdn nuerdn enurdn neurdn urnedn runedn unredn nuredn rnuedn nruedn ernudn renudn enrudn nerudn rneudn nreudn dernun edrnun drenun rdenun erdnun rednun denrun ednrun dnerun nderun endrun nedrun drneun rdneun dnreun ndreun rndeun nrdeun erndun rendun enrdun nerdun rnedun nredun ndernu dnernu nedrnu endrnu denrnu ednrnu ndrenu dnrenu nrdenu rndenu drnenu rdnenu nerdnu enrdnu nrednu rnednu erndnu rendnu dernnu edrnnu drennu rdennu erdnnu rednnu ndenru dnenru nednru endnru dennru ednnru ndneru dnneru nnderu nnderu dnneru ndneru nendru enndru nnedru nnedru enndru nendru dennru ednnru dnenru ndenru endnru nednru ndrneu dnrneu nrdneu rndneu drnneu rdnneu ndnreu dnnreu nndreu nndreu dnnreu ndnreu nrndeu rnndeu nnrdeu nnrdeu rnndeu nrndeu drnneu rdnneu dnrneu ndrneu rndneu nrdneu nerndu enrndu nrendu rnendu ernndu renndu nenrdu ennrdu nnerdu nnerdu ennrdu nenrdu nrnedu rnnedu nnredu nnredu rnnedu nrnedu ernndu renndu enrndu nerndu rnendu nrendu dernnu edrnnu drennu rdennu erdnnu rednnu denrnu ednrnu dnernu ndernu endrnu nedrnu drnenu rdnenu dnrenu ndrenu rndenu nrdenu erndnu rendnu enrdnu nerdnu rnednu nrednu
Note: these 'words' (valid or invalid) are all the permutations of the word undern. These words are obtained by scrambling the letters in undern.