There are 268 9-letter words that end with 'ous'.
Note: These 268 9-letter words that end with 'ous' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words end with ious, rous, nous, eous, lous, mous, tous, uous, gous, cous, hous, dous, pous, bous, jous, vous, kous, yous, fous, aous, sous, zous.
4-letter words end with 'ous' (3)