13 letters
- semireligious20
- sententiously19
- serendipitous19
- seriousnesses15
- serpiginously23
- silhouettists17
- sinuousnesses17
- slouchinesses21
- soulfulnesses21
- soundproofing25
- southeasterly19
- southeastward20
- southernwoods21
- southwesterly22
- southwestward23
- splendiferous23
- spontaneously22
- stercoraceous20
- stoloniferous19
- strenuousness17
- stringcourses20
- subbituminous26
- subcoriaceous24
- subreptitious21
- subterraneous19
- sulfurousness21
- sumptuousness23
- superabounded24
- supercautious22
- superfluously26
- superstitious18
- surreptitious18
- symphoniously28
- synchronously26
- tautologously21
- tediousnesses16
- temerariously20
- tempestuously24
- tenaciousness19
- tendentiously20
- tenuousnesses17
- tetradynamous21
- thermocouples26
- thermophilous25
- thoroughbrace26
- thoroughbreds24
- thoroughfares23
- thoroughgoing25
- thoroughworts23
- thoughtlessly24
- thunderclouds24
- touristically21
- transmountain20
- treacherously22
- tremulousness20
- troublemakers25
- troublemaking28
- troubleshoots20
- troublesomely24
- troublousness20
- typefoundings27
- ultracautious20
- umbelliferous26
- unaccountable27
- unaccountably29
- unadventurous23
- unambiguously28
- unboundedness23
- unceremonious23
- unconsciouses23
- unconsciously26
- uncontentious21
- uncouthnesses22
- undercounting24
- undergrounder21
- undiscouraged23
- unencouraging25
- unmaliciously26
- unpretentious20
- unrighteously23
- unseriousness17
- unsoundnesses19
- vacuousnesses23
- variousnesses19
- venturousness21
- veraciousness22
- vertiginously24
- vexatiousness26
- vicariousness22
- viciousnesses22
- viscountesses22
- viscousnesses22
- vivaciousness26
- voraciousness22
- vouchsafement30
- zealousnesses25
- zygodactylous34