clear, intelligible, severe, cold
憭 centers on mental clarity and sharp perception: being clear-headed, intelligible, or discerning. The meanings 'severe' and 'cold' likely extend from a sharp, penetrating quality of mind or atmosphere.
憭 combines 忄 (heart/mind) with 尞, which likely contributes the sound and may relate to brightness or clarity. The exact historical development is uncertain, but the structure suggests a mental quality associated with the sound リョウ.
The heart radical 忄 beside 尞 (which looks like a tall structure with a bright top) suggests a mind that is clear and sharp, like a cold, severe clarity that cuts through confusion.
For リョウ, imagine a clear, cold morning in Kyoto's Ryōan-ji garden: Ryō -> リョウ, and the serene clarity matches the kanji's meaning.