the roar of a tiger, to intimidate, to scare
猇 centers on the fierce, intimidating sound or presence of a tiger: a roar that scares or threatens. The meanings of intimidating and scaring are natural extensions of that powerful roar.
猇 combines the animal radical 犭 (beast) with 虎 (tiger), suggesting a tiger-like beast or the roar of a tiger. The exact historical development is uncertain, but the component combination directly reflects the core meaning.
A beast 犭 that is a tiger 虎: picture a tiger roaring fiercely, its sound intimidating everyone nearby. The roar is the tiger's way to scare and dominate.
For オウ, imagine the tiger's roar echoing as a deep 'OW!' sound: OW -> オウ, the intimidating cry of the beast.