junk ujnk jnuk njuk unjk nujk jukn ujkn jkun kjun ukjn kujn jnku njku jknu kjnu nkju knju unkj nukj uknj kunj nkuj knuj
Note: these 'words' (valid or invalid) are all the permutations of the word junk. These words are obtained by scrambling the letters in junk.