thumb htumb tuhmb uthmb hutmb uhtmb thmub htmub tmhub mthub hmtub mhtub tumhb utmhb tmuhb mtuhb umthb muthb humtb uhmtb hmutb mhutb umhtb muhtb thubm htubm tuhbm uthbm hutbm uhtbm thbum htbum tbhum bthum hbtum bhtum tubhm utbhm tbuhm btuhm ubthm buthm hubtm uhbtm hbutm bhutm ubhtm buhtm thmbu htmbu tmhbu mthbu hmtbu mhtbu thbmu htbmu tbhmu bthmu hbtmu bhtmu tmbhu mtbhu tbmhu btmhu mbthu bmthu hmbtu mhbtu hbmtu bhmtu mbhtu bmhtu tumbh utmbh tmubh mtubh umtbh mutbh tubmh utbmh tbumh btumh ubtmh butmh tmbuh mtbuh tbmuh btmuh mbtuh bmtuh umbth mubth ubmth bumth mbuth bmuth humbt uhmbt hmubt mhubt umhbt muhbt hubmt uhbmt hbumt bhumt ubhmt buhmt hmbut mhbut hbmut bhmut mbhut bmhut umbht mubht ubmht bumht mbuht bmuht
Note: these 'words' (valid or invalid) are all the permutations of the word thumb. These words are obtained by scrambling the letters in thumb.