Mammoth Uncensored Word List:
24 words ending with et, 11 letters long

aftermarket bittersweet breadbasket chargesheet disulphuret ferrimagnet ferromagnet fractionlet groundsheet hypermarket meadowsweet overblanket protoplanet rambouillet reinterpret retrorocket spreadsheet supermarket supersecret ultrasecret ultraviolet underbudget underjacket wastebasket