be aggravated, grow worse, grow bulky, swell
嵩 centers on a gradual increase in size, intensity, or severity: something swelling, growing bulky, or a situation worsening over time.
嵩 combines 山 (mountain) and 高 (tall, high), suggesting the towering height or bulk of a mountain. The exact historical development is uncertain, but the component combination fits the meaning of swelling or growing large.
A mountain 山 piled on top of something already tall 高 makes the whole thing swell up and grow bulky, like a situation getting worse.
For スウ, imagine a swelling mountain growing so tall it reaches the sky, where a cool breeze (スウッと) blows over its peak: スウッ -> スウ.
to mount up; to pile up; to accumulate; to increase
to be bulky; to be unwieldy; to grow voluminous
bulk; volume; quantity
raising (an embankment, levee, etc.)
to be highhanded; to be arrogant; to be overbearing
bulk density
lofty (of a mountain); tall
senior; older; elderly
having a competitive spirit
glut; overstock