\prə-ˈfau̇nd, prō-\
adj. 極深的,深厚的,深奧的
: having or showing great knowledge or understanding
: difficult to understand : requiring deep thought or wisdom
: very strongly felt
n. 深淵
: something that is very deep; specifically : the depths of the sea
When you need a word that's deeper than "deep," consider profound.
Profundus meant literally "deep" in Latin, and profound had the same meaning when it entered English in the 14th century. But even then, it also meant "figuratively deep" — that is, very great or intense: "The new laws have had a profound impact." Of people, it means "very knowledgeable or insightful," but sometimes if a person tries to sound profound they're really just giving you superficial knowledge dressed up with big words.
例句：The Chinese guqin has a long history and profound cultural meaning.
中國古琴不僅有長達的歷史意義，而且包含了很深奧的文化內涵。
