Mammoth Uncensored Word List:
44 words ending with as, 15 letters long

achondroplasias adenocarcinomas anthropophobias batrachophobias bougainvillaeas bromomenorrheas carcinosarcomas chondrosarcomas claustrophobias computerphobias cryptaesthesias dermatofibromas dermatographias dysmenorrhagias ectomycorrhizas eleutheromanias hemoglobinurias hepatoblastomas hyperaesthesias hypercalcaemias hyperglycaemias hyperlipidemias hypernatraemias hypomagnesemias hypomenorrhoeas intelligentsias intelligentzias leiomyosarcomas leucocythaemias leucocytopenias macrencephalias nephroblastomas oligocythaemias phantasmagorias phenylthioureas pseudaesthesias rangatiratangas retinoblastomas spermatorrhoeas stigmatophilias symmetrophobias telangiectasias teratoblastomas thermaesthesias