深奥 /ʂə́n ào/ Adjective

Example

• 那位教授对十四世纪税法的研究是极其【深奥的 (shēn'ào de)】。
• The professor's research into 14th-century tax law was highly esoteric.
• 强调研究的专业壁垒高，非专业人士难以进入。