The opposite of "upwords" is "downwards".

“向上”的反义词是“向下”。

youdao

When Peter had called the goats together, they started downwards.

彼得把山羊叫到一起，他们开始往下走。

youdao

She was lying face downwards on the grass.

她俯卧在草地上。

《牛津词典》

Heart-stopping switchbacks plummeted downwards between dark cliffs into a gorge cut by the Khunjerab River.

BBC: Following the Silk Road to the end of China

But expectations for Bali are low, and are being managed downwards before the meeting.

ECONOMIST: Climate change

Since the mid-1970s the long-term trend in household saving has been downwards (see chart above).

ECONOMIST: The sorry state of saving