15 letters
- phenylbutazones38
- photoduplicates29
- photosensitizes30
- phototoxicities30
- phthalocyanines30
- physiotherapies27
- phytotoxicities32
- pictorialnesses23
- pigheadednesses25
- pinealectomizes35
- pinheadednesses24
- plaintivenesses25
- platinocyanides27
- plausiblenesses25
- plenteousnesses22
- plentifulnesses26
- pneumonectomies30
- pointlessnesses21
- poliomyelitides26
- polyacrylamides31
- polynucleotides28
- polysaccharides30
- ponderousnesses22
- possessednesses20
- powerlessnesses23
- practicalnesses26
- prayerfulnesses26
- preadolescences27
- preferabilities25
- premanufactures30
- prematurenesses23
- preperformances31
- preponderancies27
- primitivenesses26
- profitabilities25
- progressivities24
- proletarianises20
- proletarianizes29
- promotabilities25
- promotivenesses26
- prosopographies28
- prostatectomies24
- provincialities27
- proximatenesses29
- psychobiologies31
- psychohistories27
- psychosurgeries28
- psychosyntheses30
- psychotherapies30
- punishabilities26
- purposivenesses27
- pusillanimities25
- quadruplicities34
- querulousnesses29
- quincentenaries31
- radioactivities23
- radiotelephones23
- rapaciousnesses23
- rapturousnesses21
- reasonabilities20
- recalcitrancies26
- recallabilities24
- receptivenesses26
- recessivenesses23
- reclusivenesses25
- reconditenesses21
- reconnaissances24
- recursivenesses24
- reductivenesses25
- reeligibilities22
- reflectometries25
- reflexivenesses31
- reformabilities25
- refractometries24
- refundabilities25
- regardfulnesses24
- regretfulnesses23
- rejuvenescences37
- religiousnesses20
- remediabilities23
- removablenesses27
- repairabilities22
- repeatabilities22
- replicabilities26
- reposefulnesses24
- representatives23
- repulsivenesses25
- requisitenesses26
- resectabilities22
- resentfulnesses22
- resistibilities19
- resistivenesses20
- respiritualizes29
- retentivenesses21
- retroactivities22
- reversibilities23
- revolutionaries22
- ribonucleosides25
- ribonucleotides25
- righteousnesses21
- roentgenologies22
- sacrosanctities22
- sagaciousnesses22
- salaciousnesses21
- saprogenicities24
- schistosomiases23
- seaworthinesses21
- seclusivenesses25
- secondarinesses21
- secretivenesses23
- sedimentologies23
- seditiousnesses18
- seductivenesses25
- selectivenesses24
- sensationalises18
- sensationalizes27
- senselessnesses18
- sensitivenesses21
- sentimentalises21
- sentimentalizes30
- separablenesses23
- shamelessnesses22
- shapelessnesses22
- shiftlessnesses22
- sightlessnesses21
- sigmoidoscopies27
- sinterabilities20
- slaughterhouses24
- sleeplessnesses21
- solderabilities21
- sorrowfulnesses24
- spectrographies28
- spermatogeneses24
- spinelessnesses21
- spinthariscopes27
- spiritualnesses21
- sporangiophores26
- spreadabilities23
- sprightlinesses24
- squeamishnesses31
- squeezabilities38
- stadtholderates20
- statelessnesses17
- steadfastnesses20
- steroidogeneses19
- stockbrokerages31
- stoichiometries23
- stratovolcanoes24
- strenuousnesses19
- strongyloidoses22
- stylelessnesses20
- sulfinpyrazones36
- sulfurousnesses23
- sumptuousnesses25
- superablenesses24
- superabundances29
- superactivities26
- superfluidities25
- superhumanities26
- supermajorities31
- supernumeraries24
- superphosphates29
- superspectacles29
- superstimulates24
- superstructures24
- supersubtleties24
- supersymmetries27
- survivabilities28
- sympathectomies31
- synchronicities27
- talkativenesses25
- tastelessnesses17
- teachablenesses25
- teleconferences27
- temperatenesses22
- temporarinesses22
- tenaciousnesses21
- tenosynovitises23
- tentativenesses21
- territorializes25
- thalassocracies24
- thanklessnesses24
- theatricalities21
- thermoregulates24
- thinkablenesses27
- thyroidectomies26
- toastmistresses18
- tomboyishnesses26
- tonsillectomies24
- toothsomenesses21
- tractablenesses23
- traditionalizes27
- transcendencies25
- transparentizes29
- tremulousnesses22
- triangularities20
- trichomonacides28
- trihalomethanes24
- troublousnesses22
- trypanosomiases24