sister isster ssiter ssiter isster sister sitser istser stiser tsiser itsser tisser sstier sstier stsier tssier stsier tssier istser sitser itsser tisser stiser tsiser sisetr issetr ssietr ssietr issetr sisetr siestr isestr seistr esistr iesstr eisstr sseitr sseitr sesitr essitr sesitr essitr isestr siestr iesstr eisstr seistr esistr sitesr istesr stiesr tsiesr itsesr tisesr sietsr isetsr seitsr esitsr iestsr eistsr steisr tseisr setisr estisr tesisr etsisr itessr tiessr ietssr eitssr teissr etissr ssteir ssteir stseir tsseir stseir tsseir ssetir ssetir sestir esstir sestir esstir stesir tsesir setsir estsir tessir etssir stesir tsesir setsir estsir tessir etssir istesr sitesr itsesr tisesr stiesr tsiesr isetsr sietsr iestsr eistsr seitsr esitsr itessr tiessr ietssr eitssr teissr etissr steisr tseisr setisr estisr tesisr etsisr sistre isstre ssitre ssitre isstre sistre sitsre istsre stisre tsisre itssre tissre sstire sstire stsire tssire stsire tssire istsre sitsre itssre tissre stisre tsisre sisrte issrte ssirte ssirte issrte sisrte sirste isrste sriste rsiste irsste risste ssrite ssrite srsite rssite srsite rssite isrste sirste irsste risste sriste rsiste sitrse istrse stirse tsirse itsrse tisrse sirtse isrtse sritse rsitse irstse ristse strise tsrise srtise rstise trsise rtsise itrsse tirsse irtsse ritsse trisse rtisse sstrie sstrie stsrie tssrie stsrie tssrie ssrtie ssrtie srstie rsstie srstie rsstie strsie tsrsie srtsie rstsie trssie rtssie strsie tsrsie srtsie rstsie trssie rtssie istrse sitrse itsrse tisrse stirse tsirse isrtse sirtse irstse ristse sritse rsitse itrsse tirsse irtsse ritsse trisse rtisse strise tsrise srtise rstise trsise rtsise sisert issert ssiert ssiert issert sisert siesrt isesrt seisrt esisrt iessrt eissrt sseirt sseirt sesirt essirt sesirt essirt isesrt siesrt iessrt eissrt seisrt esisrt sisret issret ssiret ssiret issret sisret sirset isrset sriset rsiset irsset risset ssriet ssriet srsiet rssiet srsiet rssiet isrset sirset irsset risset sriset rsiset sierst iserst seirst esirst iesrst eisrst sirest isrest sriest rsiest irsest risest serist esrist sreist rseist ersist resist iersst eirsst iresst riesst erisst reisst sserit sserit sesrit essrit sesrit essrit ssreit ssreit srseit rsseit srseit rsseit sersit esrsit sresit rsesit erssit ressit sersit esrsit sresit rsesit erssit ressit iserst sierst iesrst eisrst seirst esirst isrest sirest irsest risest sriest rsiest iersst eirsst iresst riesst erisst reisst serist esrist sreist rseist ersist resist siters isters stiers tsiers itsers tisers sietrs isetrs seitrs esitrs iestrs eistrs steirs tseirs setirs estirs tesirs etsirs itesrs tiesrs ietsrs eitsrs teisrs etisrs sitres istres stires tsires itsres tisres sirtes isrtes srites rsites irstes ristes stries tsries srties rsties trsies rtsies itrses tirses irtses ritses trises rtises sierts iserts seirts esirts iesrts eisrts sirets isrets sriets rsiets irsets risets serits esrits sreits rseits ersits resits iersts eirsts irests riests erists reists steris tseris setris estris tesris etsris streis tsreis srteis rsteis trseis rtseis sertis esrtis sretis rsetis erstis restis tersis etrsis tresis rtesis ertsis retsis iterss tierss ietrss eitrss teirss etirss itress tiress irtess ritess triess rtiess iertss eirtss iretss rietss eritss reitss teriss etriss treiss rteiss ertiss retiss ssteri ssteri stseri tsseri stseri tsseri ssetri ssetri sestri esstri sestri esstri stesri tsesri setsri estsri tessri etssri stesri tsesri setsri estsri tessri etssri sstrei sstrei stsrei tssrei stsrei tssrei ssrtei ssrtei srstei rsstei srstei rsstei strsei tsrsei srtsei rstsei trssei rtssei strsei tsrsei srtsei rstsei trssei rtssei sserti sserti sesrti essrti sesrti essrti ssreti ssreti srseti rsseti srseti rsseti sersti esrsti sresti rsesti erssti ressti sersti esrsti sresti rsesti erssti ressti stersi tsersi setrsi estrsi tesrsi etsrsi stresi tsresi srtesi rstesi trsesi rtsesi sertsi esrtsi sretsi rsetsi erstsi restsi terssi etrssi tressi rtessi ertssi retssi stersi tsersi setrsi estrsi tesrsi etsrsi stresi tsresi srtesi rstesi trsesi rtsesi sertsi esrtsi sretsi rsetsi erstsi restsi terssi etrssi tressi rtessi ertssi retssi isters siters itsers tisers stiers tsiers isetrs sietrs iestrs eistrs seitrs esitrs itesrs tiesrs ietsrs eitsrs teisrs etisrs steirs tseirs setirs estirs tesirs etsirs istres sitres itsres tisres stires tsires isrtes sirtes irstes ristes srites rsites itrses tirses irtses ritses trises rtises stries tsries srties rsties trsies rtsies iserts sierts iesrts eisrts seirts esirts isrets sirets irsets risets sriets rsiets iersts eirsts irests riests erists reists serits esrits sreits rseits ersits resits iterss tierss ietrss eitrss teirss etirss itress tiress irtess ritess triess rtiess iertss eirtss iretss rietss eritss reitss teriss etriss treiss rteiss ertiss retiss steris tseris setris estris tesris etsris streis tsreis srteis rsteis trseis rtseis sertis esrtis sretis rsetis erstis restis tersis etrsis tresis rtesis ertsis retsis
Note: these 'words' (valid or invalid) are all the permutations of the word sister. These words are obtained by scrambling the letters in sister.