The origin of the word remains obscure.

该词的来源尚不清楚。

《牛津词典》

The origin of the custom is obscure.

该习俗的起源鲜为人知。

《柯林斯英汉双解大词典》

Wooden legs are perhaps the most interesting of these prosthetics, for their origin in myth is more obscure than their true history.

木制腿在这些修复术中是最有趣的一种，因为它们神秘的起源要比它们的历史更加隐晦。

youdao

Also, despite his classical and Indian rummagings, the origin of the festival remains obscure.

ECONOMIST: Historical mendacity