15 letters
- nonintellectual25
- nonquantifiable35
- nonreproducible29
- nonsaponifiable28
- nonsedimentable26
- nontransferable25
- nucleophilicity32
- nucleosyntheses26
- nucleosynthesis26
- nucleosynthetic29
- oligonucleotide25
- optoelectronics26
- overlengthening29
- palatablenesses24
- paleobiological29
- paleobiologists25
- paleoecological29
- paleoecologists25
- paleogeographic31
- paleomagnetisms28
- paleomagnetists25
- paleontological27
- paleontologists23
- paleozoological35
- paleozoologists31
- parallelepipeds28
- peaceablenesses26
- permissibleness26
- phenolphthalein31
- photodegradable28
- photoelectronic28
- phototelegraphy30
- pinealectomized36
- pinealectomizes35
- plausiblenesses25
- pleasurableness25
- plenipotentiary26
- plenteousnesses22
- plentifulnesses26
- plethysmographs33
- plethysmography35
- pleuropneumonia29
- pointlessnesses21
- polyelectrolyte28
- polynucleotides28
- postadolescents24
- postmillenarian25
- powerlessnesses23
- practicableness29
- preadolescences27
- premillenarians25
- premillennially29
- presentableness24
- problematically32
- proletarianised21
- proletarianises20
- proletarianized30
- proletarianizes29
- purposelessness24
- pyroelectricity29
- radiotelegraphs24
- radiotelegraphy26
- radiotelemetric23
- radiotelephones23
- reconstructible27
- reflectometries25
- reflexivenesses31
- refrangibleness26
- remorselessness20
- removablenesses27
- respectableness26
- responsibleness24
- retroreflection23
- retroreflective26
- retroreflectors22
- ribonucleosides25
- ribonucleotides25
- sclerotizations29
- selectivenesses24
- semisubmersible29
- senselessnesses18
- separablenesses23
- serviceableness27
- shamelessnesses22
- shapelessnesses22
- shiftlessnesses22
- sightlessnesses21
- sledgehammering30
- sleeplessnesses21
- spinelessnesses21
- splendiferously28
- splenectomizing38
- statelessnesses17
- steeplechasings27
- stylelessnesses20
- subproletariats23
- superablenesses24
- supercalendered26
- superelevations25
- superspectacles29
- supersubtleties24
- supplementation28
- susceptibleness27
- tastelessnesses17
- teachablenesses25
- teleconferenced28
- teleconferences27
- telegraphically30
- telekinetically28
- telephotography30
- teleprocessings25
- teletypewriters24
- tetramethyllead25
- thanklessnesses24
- thinkablenesses27
- thoughtlessness24
- tonsillectomies24
- tractablenesses23
- troubleshooters22
- troubleshooting25
- troublesomeness24
- unalterableness23
- uncategorizable35
- unchallengeable31
- uncleanlinesses24
- unclimbableness32
- uncompromisable33
- uncopyrightable33
- underprivileged29
- undesirableness23
- unendurableness25
- unexceptionable35
- unfavorableness29
- unknowledgeable33
- unobjectionable37
- unpronounceable30
- unsettlednesses20
- valetudinarians24
- valuelessnesses23
- venerablenesses25
- veritablenesses24
- versatilenesses21
- voicelessnesses24
- warrantableness24
- waterlessnesses20
- whistleblowings31
- wholesomenesses25
- worthlessnesses22