running water; flowing water; stream
Refers to water that is moving, as opposed to still water. Can be used for natural streams or any flowing water, including in technical contexts.
This river never stops flowing all year round.
Wash your hands under running water.
mutual love; reciprocated love
going with the flow; free and unconstrained
high mountains and flowing water; sublime natural scenery · sublime music; exquisite performance
Compound of 流 (ryū, 'flow') + 水 (sui, 'water'). The reading is on'yomi, and the word is straightforwardly derived from its kanji components.