Mammoth Uncensored Word List:
31 words ending with om, 10 letters long

bellbottom bridegroom bugbeardom changeroom cockneydom coffeeroom crippledom demirepdom disembosom disselboom engineroom enthraldom flunkeydom fresherdom heathendom heteroatom kaffirboom kitchendom livingroom nonfreedom reaccustom rockbottom saddleroom schoolroom sheriffdom streetroom strongroom subkingdom whiskbroom witchbroom witgatboom