undefinable
adj. 无法定义的；不确定的
同义词
参考例子
1.Some undefinable time later, Obi-Wan felt his head and shoulders breach the surface of the lightless ocean.
不知过了多久，欧比旺终于感觉到脑袋和双肩浮出了那暗无天日的海洋的水面。
2.The magical photograph attempts to go beyond the immediate context of the recorded experience into realm of the undefinable.
具有魔幻般的照片试图超越媒体本身，从而将记录的体验放在一个难以界定的领域之中。
3.Although most people have the essentials of living taken care of, they still have an undefinable emptiness within their hearts.
虽然，人活在繁华的生活中，但大多数的人，内心弥漫着一股莫可名状的处空，苦闷和抑郁。
英文解释
adj.
1.not capable of being precisely or readily described; not easily put into words
网络释义
undefinable
不可命名;