Sentence:  "It's all <WSD>Greek</WSD> to me," said my companion at the outset, but as the warrior continued, his fears arose within him; it might be sentence of death—what did he know what it might not be? 
Meaning of the word marked with <WSD> tags:  Unintelligible speech or text, such as foreign speech or text, or regarding subjects the listener is not familiar with, such as mathematics or technical jargon; or statements that the listener does not understand or agree with.