17 letters
- perchloroethylene32
- permissiblenesses28
- phenylethylamines35
- picturesquenesses35
- plainspokennesses31
- pleasurablenesses27
- plenipotentiaries26
- polycondensations30
- postmillennialism31
- postmillennialist28
- practicablenesses31
- precipitatenesses27
- prefigurativeness31
- premillenarianism30
- premillennialisms31
- premillennialists28
- presentablenesses26
- pretentiousnesses23
- progressivenesses27
- prohibitivenesses30
- provocativenesses32
- pseudoparenchymas36
- quadricentennials35
- quarrelsomenesses32
- quatercentenaries32
- recentralizations32
- refrangiblenesses28
- renationalization30
- reprehensibleness28
- respectablenesses28
- responsiblenesses26
- restrictivenesses25
- roentgenographies28
- rudimentarinesses24
- schizophrenically44
- semidocumentaries29
- sententiousnesses21
- serviceablenesses29
- sesquicentenaries32
- sesquicentennials34
- splendiferousness28
- subordinatenesses24
- substantivenesses27
- superefficiencies34
- superintelligence30
- superintendencies28
- superlativenesses27
- superregenerative28
- suppressivenesses29
- susceptiblenesses29
- suspensefulnesses28
- teleconferencings32
- tendentiousnesses22
- tenderheartedness23
- thermoluminescent32
- thrombocytopenias34
- transcendentalism28
- transcendentalist25
- transgenerational23
- transparentnesses23
- triboluminescence33
- trichloroethylene29
- tridimensionality26
- triphenylmethanes32
- troublesomenesses26
- ultracentrifuging32
- unalterablenesses25
- unclimbablenesses34
- uncompetitiveness33
- uncomprehendingly38
- unconventionality32
- underachievements33
- underdevelopments33
- undernourishments28
- undesirablenesses25
- unendurablenesses27
- unfashionableness30
- unfavorablenesses31
- unidimensionality28
- unobtrusivenesses28
- unpretentiousness25
- venturesomenesses27
- videoconferencing36
- warrantablenesses26