roar, howl, recite emotionally, feign indifference
嘯 centers on producing a loud, drawn-out vocal sound: roaring, howling, or reciting with strong emotion. The sense of feigning indifference is a figurative extension where one puts on a loud or dismissive front.
嘯 combines 口 (mouth) with 肅, which likely contributes the sound and may suggest a solemn or drawn-out quality. The exact historical development of the compound is uncertain.
A mouth 口 beside the solemn, drawn-out shape 肅: imagine a person opening their mouth wide to let out a long, emotional roar or howl.
For ショウ, picture a dramatic show where an actor roars and howls on stage: show -> ショウ, and the mouth 口 delivers the performance.