indescribable
adj. 难以形容的；莫名其妙的；不能用语言表达的
例句
How can I bring myself, next New Year, to offer them miserable pellets of something indescribable?
在新的一年里，我怎样才能给他们提供一些难以形容的东西呢？
The pain was indescribable.
疼痛得无法形容。
《牛津词典》
An expression of indescribable happiness shone in her countenance, though tears were rolling down her cheeks.
她脸上流露出一种说不出的幸福的表情，虽然眼泪从脸上滚落下来。
