small evergreen shrub
檟 refers to a small evergreen shrub. The meaning is narrow and botanical, without broader abstract extensions.
檟 combines 木 (tree) with 賈, which likely contributes the sound. The character is used for a specific shrub, but the detailed historical development is uncertain.
The tree radical 木 on the left suggests a woody plant, and the right side 賈 looks like a dense, bushy shape. Picture a small evergreen shrub with thick foliage.
For カ, imagine a small shrub shaped like a car: car -> カ, and the evergreen leaves make it look like a tiny green vehicle.