This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
宭 combines 宀 (roof) with 君, but the exact historical development and original meaning are uncertain.
A roof 宀 over a ruler 君 suggests a sheltered or enclosed space for a leader, but the actual meaning is unclear.
For クン, imagine a coon (raccoon) hiding under the roof 宀 with the ruler 君: coon -> クン.