This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
暙 combines 日 (sun/day) with 春 (spring). The exact historical development is uncertain, but it likely relates to spring sunlight or a spring day.
The sun 日 beside spring 春 suggests a warm spring day, but the kanji's actual meaning is unclear.
For シュン, picture a spring 春 day so perfect that it feels like a shun (シュン) moment of pure sunshine 日.
—