This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 隁 is uncertain. It combines the mound radical ⻖ with the phonetic component 匽, but its original meaning and usage are unclear.
The mound radical ⻖ suggests earth or a barrier, and the right side 匽 may hint at something hidden or enclosed. Picture a hidden earthen embankment, but remember the meaning is uncertain.
For エン, imagine an earthen embankment ending in a hidden enclosure: end -> エン, tying the shape to the reading.