15 letters
- phenylthioureas27
- photojournalism35
- photojournalist32
- platitudinously26
- plenteousnesses22
- ponderousnesses22
- precipitousness26
- prestigiousness22
- pretentiousness21
- promiscuousness27
- psychoacoustics32
- pulchritudinous29
- punctiliousness26
- pusillanimously29
- querulousnesses29
- rapaciousnesses23
- rapturousnesses21
- religiousnesses20
- repetitiousness20
- resourcefulness25
- righteousnesses21
- roundheadedness23
- rumbustiousness25
- sagaciousnesses22
- salaciousnesses21
- sanctimoniously27
- saponaceousness24
- seditiousnesses18
- sententiousness19
- serendipitously24
- slaughterhouses24
- splendiferously28
- spontaneousness22
- strenuousnesses19
- subreptitiously26
- subterraneously24
- sulfurousnesses23
- sumptuousnesses25
- superfluousness26
- superstitiously23
- surreptitiously23
- synchronousness26
- temerariousness20
- tempestuousness24
- tenaciousnesses21
- tendentiousness20
- thoughtlessness24
- treacherousness22
- tremulousnesses22
- troubleshooters22
- troubleshooting25
- troublesomeness24
- troublousnesses22
- ultrafastidious22
- unboundednesses25
- unceremoniously28
- unconsciousness26
- unfossiliferous25
- unmelodiousness24
- unpretentiously25
- unpronounceable30
- unrighteousness23
- unseriousnesses19
- venturousnesses23
- veraciousnesses24
- vexatiousnesses28
- vicariousnesses24
- vicissitudinous26
- vivaciousnesses28
- voraciousnesses24