This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 抎 is uncertain. It visually contains 扌 (hand) and 云, but the original semantic and phonetic roles are unclear.
Since the meaning is unclear, focus on the shape: a hand 扌 beside 云, like a hand holding a cloud. Use this image to remember the character, but do not attach a fixed meaning.
For ウン, imagine a hand waving through a cloud with a soft 'un' sound: un -> ウン. The scene ties the shape to the reading without relying on a known meaning.