bridge
彴 centers on a bridge, specifically a simple wooden footbridge or log bridge. The meaning is narrow and concrete.
彴 combines 彳 (movement, step) with 勺, which likely contributes a phonetic element. The exact historical development is uncertain, but the character is associated with a simple bridge or crossing.
The left side 彳 suggests stepping or walking, and the right side 勺 looks like a ladle or a curved shape. Imagine stepping across a curved log bridge: 彴 is a simple bridge.
For ハク, picture a hiker crossing a log bridge and saying 'hack' as they step over a rough spot: hack -> ハク, and the hiker crosses the bridge.