noun, noun which may take the genitive case particle 'no'
swift current; rapids
Refers to a fast-flowing part of a river, often used in descriptions of nature, geography, or metaphorical rapid change.
この川は急流が多いので、カヌーには向かない。
This river has many rapids, so it's not suitable for canoeing.
The sound of the swift current could be heard from afar.
急流 explicitly means a fast, rushing current, whereas 瀬 refers more specifically to the particular rapid section of a river.
急流 is the general term for a fast-flowing torrent, while 早瀬 specifically names a swift, shallow stretch of a river and is common in place names.
急流 is the common, everyday word for a fast-flowing current, while 滝川 is a rarer, more literary term evoking a waterfall-like torrent.
急流 emphasizes the speed of a current, while 激流 emphasizes its violent, raging force.
清流 describes water that is clear, while 急流 describes water that is fast-moving; the two qualities are unrelated despite the shared 流 character.
river rafting; shooting the rapids
Compound of 急 (kyū, 'rapid') and 流 (ryū, 'flow, current'). The reading is on'yomi.