This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
椻 combines 木 (tree/wood) with 匽, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side is a tree 木, and the right side 匽 contains a hidden woman 女 inside a box 匚 under the sun 日. Without a clear meaning, picture a mysterious wooden box under a tree, its purpose unknown.
For エン, imagine the wooden box under the tree is an enigma: en -> エン, and the kanji remains a puzzle.