This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 穾 is uncertain. It visually combines 穴 (hole, cavity) and 夭 (early death, calamity), but the original meaning and component relationship are unclear.
With no clear meaning, picture a deep hole (穴) where something calamitous (夭) is hidden, but what it represents is a mystery.
For ヨウ, imagine a yawning (ヨウ) hole (穴) that swallows things early (夭), but the sound is all that's left.