Common compounds: 灭火 (put out fire), 灭火器 (fire extinguisher), 消灭 (annihilate), 灭绝 (extinct), 灭亡 (perish). 灭 carries a sense of finality — complete elimination.
usage
Simplified 灭 shows 一 (a lid) over 火 (fire) — putting a lid over fire to extinguish it.