far, distant
夐 centers on great distance or remoteness: something far away in space or time.
The historical origin of 夐 is uncertain. The modern form visually contains elements such as 目 (eye) and 夂 (go slowly), but their exact role in the character's development is unclear.
The character looks like an eye 目 peering into the distance under a covering 冂, with legs 夂 suggesting a long journey. Imagine straining to see something far away.
For ケイ, picture a distant kay (ケイ) floating on the horizon, so far you can barely see it.