fleas lfeas felas eflas lefas elfas flaes lfaes fales afles lafes alfes feals efals faels afels eafls aefls leafs elafs laefs alefs ealfs aelfs flesa lfesa felsa eflsa lefsa elfsa flsea lfsea fslea sflea lsfea slfea fesla efsla fsela sfela esfla sefla lesfa elsfa lsefa slefa eslfa selfa flase lfase false aflse lafse alfse flsae lfsae fslae sflae lsfae slfae fasle afsle fsale sfale asfle safle lasfe alsfe lsafe slafe aslfe salfe feasl efasl faesl afesl eafsl aefsl fesal efsal fseal sfeal esfal sefal fasel afsel fsael sfael asfel safel easfl aesfl esafl seafl asefl saefl leasf elasf laesf alesf ealsf aelsf lesaf elsaf lseaf sleaf eslaf selaf lasef alsef lsaef slaef aslef salef easlf aeslf esalf sealf aself saelf
Note: these 'words' (valid or invalid) are all the permutations of the word fleas. These words are obtained by scrambling the letters in fleas.