embers
燼 centers on the last glowing remains of a fire: embers, the dying but still hot residue after flames have subsided.
燼 combines 火 (fire) with 盡 (exhaust, use up), suggesting fire that has burned down to its last remnants. The exact historical development of 盡 is complex, but the phono-semantic structure is clear.
Fire 火 on the left, and 盡 (exhaust) on the right: picture a fire that has exhausted its fuel, leaving only glowing embers behind.
For ジン, imagine a gin and tonic being warmed over the last embers of a campfire: gin -> ジン, and the embers keep the drink just warm enough.
ash; embers; complete destruction
smouldering fire; smoldering fire; embers
to be reduced to ashes; to be incinerated; to be destroyed by fire
to be reduced to ashes; to be incinerated; to be destroyed by fire
completely destroying (esp. by fire); burning to ashes