cover, suffocate, obstruct
奄 centers on the idea of covering or overwhelming something so completely that it is smothered or blocked: covering, suffocating, or obstructing.
奄 is thought to combine 大 (big) with 电 (a form related to covering or spreading), suggesting something large that covers or overwhelms. The exact historical development is uncertain.
The top 大 (big) spreads over the lower 电 like a heavy lid, covering and suffocating whatever is underneath.
For エン, imagine a huge lid covering everything and creating an enclosed, airless space: the word 'end' (エン) fits because the air is ended.
gasping
Amami rabbit (Pentalagus furnessi); Ryukyu rabbit
white-spotted pufferfish (Torquigener albomaculosus)
Ryukyu spiny rat (Tokudaia osimensis)
stout chromis (Chromis chrysura)
Amami tip-nosed frog (Odorrana amamiensis)
gasping for breath; at one's last gasp; breathing feebly; on the brink of death; more dead than alive