深奥 (shēn ào) is an adjective meaning 'profound' or 'abstruse' — describing ideas, theories, texts, or concepts that are deeply complex, difficult to understand, and often require specialized knowledge or deep reflection. The first character 深 (shēn) means 'deep', suggesting depth of thought or insight; the second character 奥 (ào) means 'profound', 'mysterious', or 'hidden', implying something not immediately apparent or accessible. Together, they emphasize intellectual depth and obscurity rather than physical depth.

This word is commonly used in academic, philosophical, scientific, or literary contexts — for example, when discussing classical philosophy, advanced mathematics, or ancient religious texts. It carries a neutral-to-respectful connotation: calling something 深奥 acknowledges its intellectual weight, but may also subtly imply it’s challenging for ordinary readers. It is rarely used for everyday objects or simple situations — you wouldn’t describe a sandwich or a bus schedule as 深奥.