16 letters
- transnationalism23
- transportability26
- transsexualities26
- ultraliberalisms26
- ultralightweight30
- ultranationalism24
- ultranationalist21
- unaccountability32
- unalterabilities23
- unavailabilities27
- unavailingnesses27
- uncommercialized41
- uncongenialities26
- undecidabilities27
- undercapitalized36
- underutilization31
- undesirabilities23
- unflappabilities32
- unfriendlinesses25
- ungrammaticality32
- unindustrialized32
- universalization33
- unmannerlinesses25
- unpalatabilities26
- unpredictability31
- unsubstantiality26
- unthinkabilities29
- untouchabilities28
- upgradeabilities27
- weatherabilities25
- whatchamacallits34