nxid xnid nixd inxd xind ixnd nxdi xndi ndxi dnxi xdni dxni nidx indx ndix dnix idnx dinx xidn ixdn xdin dxin idxn dixn
Note: these 'words' (valid or invalid) are all the permutations of the word nxid. These words are obtained by scrambling the letters in nxid.