This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
偆 combines 亻 (person) with 春 (spring), but the exact historical development and original meaning are uncertain.
A person 亻 beside spring 春, but the meaning is unclear. Perhaps imagine someone emerging in spring, but treat this as a guess.
For シュン, think of the spring season 春 (しゅん) itself: 春 -> シュン, and the person 亻 is enjoying the spring weather.