Mammoth Uncensored Word List:
42 words ending with th, 11 letters long

aftergrowth breechcloth bridewealth chaetognath chainlength cheesecloth coppersmith cottonmouth countermyth decillionth downtoearth footbreadth gazillionth groatsworth hairbreadth hammercloth handbreadth houndsteeth houndstooth intergrowth littleworth luckenbooth nonillionth octillionth peristalith plectognath saddlecloth seventeenth silversmith sixtyeighth sixtyfourth supergrowth supersleuth supersmooth thenceforth trilliardth twelvemonth twentyfifth ultrasmooth underbreath undergrowth whenceforth