filth iflth flith lfith ilfth lifth fitlh iftlh ftilh tfilh itflh tiflh fltih lftih ftlih tflih ltfih tlfih iltfh litfh itlfh tilfh ltifh tlifh filht iflht fliht lfiht ilfht lifht fihlt ifhlt fhilt hfilt ihflt hiflt flhit lfhit fhlit hflit lhfit hlfit ilhft lihft ihlft hilft lhift hlift fithl ifthl ftihl tfihl itfhl tifhl fihtl ifhtl fhitl hfitl ihftl hiftl fthil tfhil fhtil hftil thfil htfil ithfl tihfl ihtfl hitfl thifl htifl flthi lfthi ftlhi tflhi ltfhi tlfhi flhti lfhti fhlti hflti lhfti hlfti fthli tfhli fhtli hftli thfli htfli lthfi tlhfi lhtfi hltfi thlfi htlfi ilthf lithf itlhf tilhf ltihf tlihf ilhtf lihtf ihltf hiltf lhitf hlitf ithlf tihlf ihtlf hitlf thilf htilf lthif tlhif lhtif hltif thlif htlif
Note: these 'words' (valid or invalid) are all the permutations of the word filth. These words are obtained by scrambling the letters in filth.