often foten otfen tofen ftoen tfoen ofetn foetn oeftn eoftn feotn efotn otefn toefn oetfn eotfn teofn etofn fteon tfeon feton efton tefon etfon oftne fotne otfne tofne ftone tfone ofnte fonte onfte nofte fnote nfote otnfe tonfe ontfe notfe tnofe ntofe ftnoe tfnoe fntoe nftoe tnfoe ntfoe ofent foent oefnt eofnt feont efont ofnet fonet onfet nofet fnoet nfoet oenft eonft oneft noeft enoft neoft fenot efnot fneot nfeot enfot nefot otenf toenf oetnf eotnf teonf etonf otnef tonef ontef notef tnoef ntoef oentf eontf onetf noetf enotf neotf tenof etnof tneof nteof entof netof fteno tfeno fetno eftno tefno etfno ftneo tfneo fnteo nfteo tnfeo ntfeo fento efnto fneto nfeto enfto nefto tenfo etnfo tnefo ntefo entfo netfo
Note: these 'words' (valid or invalid) are all the permutations of the word often. These words are obtained by scrambling the letters in often.