be bare, nude
臝 centers on the state of being uncovered or exposed: bareness or nudity. The two given meanings are direct expressions of this same idea.
The exact historical development of 臝 is uncertain. It appears to be a complex character with an outer enclosure and inner 果, but the original component relationships are not clearly established.
The character looks like a body wrapped in a loose covering, with 果 (fruit) inside suggesting something exposed like a peeled fruit. Picture a figure shedding its outer layer to stand bare.
For ラ, imagine a person standing bare in a raw, natural state: raw -> ラ, and the exposed figure matches the nude meaning.