sperm pserm seprm esprm pesrm epsrm sprem psrem srpem rspem prsem rpsem serpm esrpm srepm rsepm erspm respm persm eprsm presm rpesm erpsm repsm spemr psemr sepmr espmr pesmr epsmr spmer psmer smper msper pmser mpser sempr esmpr smepr msepr emspr mespr pemsr epmsr pmesr mpesr empsr mepsr sprme psrme srpme rspme prsme rpsme spmre psmre smpre mspre pmsre mpsre srmpe rsmpe smrpe msrpe rmspe mrspe prmse rpmse pmrse mprse rmpse mrpse sermp esrmp sremp rsemp ersmp resmp semrp esmrp smerp mserp emsrp mesrp srmep rsmep smrep msrep rmsep mrsep ermsp remsp emrsp mersp rmesp mresp perms eprms prems rpems erpms repms pemrs epmrs pmers mpers emprs meprs prmes rpmes pmres mpres rmpes mrpes ermps remps emrps merps rmeps mreps
Note: these 'words' (valid or invalid) are all the permutations of the word sperm. These words are obtained by scrambling the letters in sperm.