tartar horn, chilly wind
觱 is a rare kanji with two distinct senses: a tartar horn (a type of wind instrument) and a chilly wind. The connection is likely through the idea of a piercing, cold blast of air or sound.
The exact historical development of 觱 is uncertain. It combines 咸 (which can relate to a piercing sound or all) and 角 (horn), suggesting a horn that produces a sharp, cold blast.
The top 咸 looks like a mouth blowing hard, and the bottom 角 is a horn. Imagine a tartar horn producing a blast so cold it feels like a chilly wind.
For ヒツ, picture a horn player taking a deep breath and letting out a sharp 'hits' sound: hits -> ヒツ, like the blast of the tartar horn.