17 letters
- reprehensibleness28
- reproachfulnesses31
- reproducibilities29
- resolidifications26
- resourcefulnesses27
- respectablenesses28
- responsiblenesses26
- restrictivenesses25
- revolutionariness25
- roentgenographies28
- roundheadednesses25
- rudimentarinesses24
- rumbustiousnesses27
- sanctimoniousness27
- saponaceousnesses26
- semiconsciousness29
- semidocumentaries29
- semidomestication28
- semipornographies31
- semiprofessionals28
- sententiousnesses21
- serviceablenesses29
- sesquicentenaries32
- sesquicentennials34
- softheartednesses24
- splendiferousness28
- spontaneousnesses24
- standoffishnesses28
- stereochemistries25
- stereomicroscopes29
- straitlacednesses23
- structurelessness24
- subordinatenesses24
- substantialnesses24
- substantivenesses27
- superbillionaires27
- superefficiencies34
- superfluousnesses28
- superintendencies28
- superlativenesses27
- supermillionaires27
- superplasticities28
- suppressibilities28
- suppressivenesses29
- susceptiblenesses29
- suspensefulnesses28
- swellheadednesses27
- symmetricalnesses30
- synchronousnesses28
- telephotographies30
- temerariousnesses22
- tempestuousnesses26
- tendentiousnesses22
- tenderheartedness23
- thermochemistries30
- thermoluminescent32
- thermostabilities26
- thoughtlessnesses26
- tightfistednesses26
- transferabilities25
- translatabilities23
- transparentnesses23
- transubstantiates23
- treacherousnesses24
- triboluminescence33
- triiodothyronines24
- triphenylmethanes32
- troublesomenesses26
- trueheartednesses22
- trustworthinesses24
- ultraprofessional27
- ultraprogressives28
- ultrasonographies27
- unacceptabilities32
- unalterablenesses25
- unanswerabilities27
- unassailabilities24
- unceremoniousness28
- unchangeabilities31
- unclimbablenesses34
- uncompetitiveness33
- unconcernednesses29
- unconsciousnesses28
- underhandednesses26
- undesirablenesses25
- unemployabilities32
- unendurablenesses27
- unfashionableness30
- unfavorablenesses31
- unforgivingnesses32
- uninhibitednesses27
- unmelodiousnesses26
- unmitigatednesses26
- unobtrusivenesses28
- unpretentiousness25
- unrighteousnesses25
- venturesomenesses27
- viscoelasticities28
- warmheartednesses27
- warrantablenesses26
- wrongheadednesses28
- xeroradiographies32