12 letters
- semiprecious22
- senatorships18
- shipbuilders23
- shipbuilding26
- shipwrecking30
- showmanships26
- sideslipping23
- siphonophore23
- siphonostele19
- slipperiness20
- slipstreamed20
- sniperscopes22
- soldierships19
- speakerships24
- sponsorships21
- stewardships21
- stipulations18
- stripteasers15
- studentships20
- submultiples25
- subprincipal27
- subscription23
- superscripts22
- survivorship26
- traineeships18
- transhipping24
- transshipped22
- tribuneships22
- triphosphate22
- triphthongal23
- tripinnately20
- triplicating22
- triplication20
- triplicities19
- trusteeships18
- undeciphered24
- undiplomatic25
- unprincipled26
- unripenesses18
- unscriptural22
- venipuncture26
- viceroyships26
- viviparities23
- viviparously27
- watermanship24
- whippletrees24
- whippoorwill28
- whipstitched26
- whipstitches25
- workmanships28
- worshipfully28
- xiphisternum29