This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 猒 is uncertain. It visually contains 犬 (dog) over 日 (sun) and 月 (moon), but this may not reflect its original composition.
With no clear meaning, focus on the shape: a dog 犬 sitting above the sun 日 and moon 月, like a mythical creature watching over day and night.
For エン, imagine the dog 犬 in 猒 is actually a mystical 'en' (a made-up name) that guards the sun and moon: en -> エン.