destruction
兦 centers on destruction, ruin, or ceasing to exist. It is a rare kanji with a narrow meaning.
The exact historical development of 兦 is uncertain. It may be an ancient variant or simplified form related to 亡, but the component relationship is not clearly established.
The shape looks like 入 (enter) trapped inside a broken enclosure, as if entering a place that is falling apart—destruction.
For ボウ, imagine a bow breaking apart: bow -> ボウ, and the destruction leaves only fragments.