expression, noun
bottomless ravine; abyss
Literary or figurative expression for an extremely deep, seemingly bottomless gorge. Often used metaphorically for a profound or dangerous situation.
彼は千尋の谷に落ちるような絶望を感じた。
He felt a despair like falling into a bottomless abyss.
深淵 is a more common and neutral word for 'abyss' or 'deep chasm', while 千尋の谷 is a set phrase with a classical, literary feel.
千尋 means 'a thousand fathoms' (尋 being a traditional unit of depth), and 谷 means 'valley' or 'ravine'. The phrase literally means 'a valley of a thousand fathoms', i.e., an immeasurably deep gorge.