15 letters
- psychogenically35
- punishabilities26
- pusillanimities25
- pusillanimously29
- pyrotechnically33
- quincentennials33
- recognizability36
- recolonizations30
- recommissioning28
- reorganizations28
- republicanizing39
- repudiationists21
- reservationists20
- restrengthening24
- restrictionisms22
- restrictionists19
- resurrectionist20
- revolutionising25
- revolutionizers31
- revolutionizing34
- sanctimoniously27
- saponifications26
- saprogenicities24
- segregationists20
- semicentennials25
- semicolonialism27
- servomechanisms31
- snippersnappers29
- suborganization32
- suburbanization34
- superconvenient29
- superhumanities26
- synchronicities27
- synchronisation25
- synchronization34
- thyrocalcitonin28
- totalitarianism20
- totalitarianize26
- trinitrotoluene19
- ultimogenitures24
- ultraconvenient27
- ultramodernists22
- ultramontanisms25
- unceremoniously28
- uncommunicative35
- uncomplainingly34
- uniformitarians24
- unimaginatively30
- uninformatively31
- uninhibitedness25
- unintelligently26
- unintentionally24
- uninterruptedly26
- universalnesses23
- unquestioningly34
- utilitarianisms21
- vivisectionists27
- westernisations20
- westernizations29