The word 坏事 is formed by directly combining the character 坏 (huài), which means "bad" or "to spoil", with the character 事 (shì), which means "matter", "affair", or "event". This creates a conceptual unit where the quality of "badness" is inherently attached to the "matter", resulting in a meaning that encompasses either a "bad thing/deed" as a noun or the act of "ruining something" as a verb, with the core idea always centered on a matter that is spoiled or harmful.