pit, hole
臽 centers on a sunken hollow in the ground: a pit or hole, often used as a trap.
臽 is thought to combine ⺈ (a person bending over) with 臼 (a mortar or hollow), suggesting a person falling into a pit or hollow. The exact historical development is uncertain.
The top ⺈ looks like a person leaning over, and the bottom 臼 is a hollow mortar. Picture someone peering into a deep pit or hole.
For カン, imagine a can falling into a pit: can -> カン, and the hollow 臼 catches it.