neifs enifs niefs inefs einfs ienfs nefis enfis nfeis fneis efnis fenis nifes infes nfies fnies ifnes fines eifns iefns efins feins ifens fiens neisf enisf niesf inesf einsf iensf nesif ensif nseif sneif esnif senif nisef insef nsief snief isnef sinef eisnf iesnf esinf seinf isenf sienf nefsi enfsi nfesi fnesi efnsi fensi nesfi ensfi nsefi snefi esnfi senfi nfsei fnsei nsfei snfei fsnei sfnei efsni fesni esfni sefni fseni sfeni nifse infse nfise fnise ifnse finse nisfe insfe nsife snife isnfe sinfe nfsie fnsie nsfie snfie fsnie sfnie ifsne fisne isfne sifne fsine sfine eifsn iefsn efisn feisn ifesn fiesn eisfn iesfn esifn seifn isefn siefn efsin fesin esfin sefin fsein sfein ifsen fisen isfen sifen fsien sfien
Note: these 'words' (valid or invalid) are all the permutations of the word neifs. These words are obtained by scrambling the letters in neifs.