cloud cover
靆 centers on a thick, overcast sky: a state of cloud cover or gloomy weather.
靆 combines 雲 (cloud) with 逮, which likely contributes the sound タイ. The character is used to describe dense cloud cover.
The left side is 雲 (cloud), and the right side 逮 suggests something spreading or covering. Picture a thick cloud layer spreading across the sky, creating heavy cloud cover.
For タイ, imagine a thick cloud cover that ties up the sky: tie -> タイ, and the clouds are tied together in a dense overcast layer.
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trailing (clouds); thick; heavy