bark, bay, howl, bellow, roar, cry
吼 centers on loud, forceful vocalizations from the throat: barking, howling, roaring, bellowing, or crying out.
吼 combines 口 (mouth) with 孔, which likely contributes the sound and may suggest an opening or hole, together expressing a loud sound from the mouth.
A mouth 口 beside 孔 (a hole or opening) suggests a wide-open mouth producing a loud bark, howl, or roar.
For コウ, imagine a dog barking so loudly it sounds like a cough: cough -> コウ, and the bark echoes from its open mouth.