This is the 5661st most frequent Japanese word.
すい
"すい" (sui) can mean "essence," "refined," or "pure" depending on context.
In this sentence, 'すい' modifies 'なる空' to describe a clear and pure sky.
今日は天気がすごくいいね、すいなる空が広がってる。
The weather is really nice today, with a clear sky spread out.
Here, 'すい' is used metaphorically to describe music that is tranquil and pure.
やっぱりすい音楽には心が癒される。
As expected, soothing music heals the soul.
'すい' is utilized to depict food that tastes clear, fresh, or untainted.