Sometimes the fall is minor, other times you tumble downstairs or plummet off a cliff into a chasm.

这还算轻的，有时甚至是从楼上摔下去，甚至从悬崖摔落到山间裂缝中。

youdao

I would tell him to, "Jump off that cliff." be rebuffed by a, "No, are you crazy?" hit back with, "you are a coward." and then happily watch him tumble to the bottom of the gorge.

我要告诉他，“跳下悬崖的。”被拒绝了，“不，是你疯了吗？”回击了，“你是一个懦夫。”然后愉快地看着他跌倒在底部的峡谷。

youdao

The authors even identified a universal "tipping point" in the life cycle of new words: Roughly 30 to 50 years after their birth, they either enter the long-term lexicon or tumble off a cliff into disuse.

WSJ: Culturomics Looks at the Birth and Death of Words

Add in an anaemic recovery, at best, in America, and the worry that its economy might tumble off a fiscal cliff in December, and the outlook for external demand is bleak.

ECONOMIST: Banyan