unspeakable
adjective uk/ʌnˈspiː.kə.bəl/ us/ʌnˈspiː.kə.bəl/
不堪入耳的；难以说出口的；无法用言语形容的
too bad or shocking to be expressed in words
unspeakable crimes 极其残忍的罪行
No report can convey the unspeakable suffering that this war has caused. 这场战争所造成的痛苦无法形容，没有甚么报道能够传达出来。
The stench coming from the toilets was unspeakable. 从卫生间散发出来的气味臭不可闻。
Compare: indescribable