Mammoth Uncensored Word List:
25 words ending with x, 11 letters long

androsphinx arbitratrix chalcedonyx coexecutrix consolatrix demultiplex fricandeaux hydrothorax hypopharynx merveilleux nasopharynx negotiatrix neoorthodox nonorthodox overcomplex photosyntax progenitrix prolocutrix proprietrix prosecutrix sacrococcyx sceuophylax speculatrix thereminvox thoroughwax