Using all letters

                                                                           excellencies

                                                                          The other words:

                                                                               excel

                                                                            excellence

                                                                            excellences

                                                                              excels

                                                                              excess

                                                                             excesses

                                                                              excise

                                                                              excises

                                                                               execs

                                                                               exile

                                                                              exiles

                                                                              exilic

                                                                               nixes

                                                                               nixie

                                                                              nixies

                                                                               sexes

                                                                             sexiness

                                                                              sexless

                                                                            sexlessness

                                                                               silex

                                                                               sixes

                                                                               xenic

                                                                               xxiii