‘事后’ literally combines 事 (shì, 'matter' or 'event') and 后 (hòu, 'after' or 'behind'), meaning 'after the event' or 'afterwards'. It functions primarily as an adverb indicating a time point following a specific incident, action, or situation — often one that has just occurred or is being discussed. Unlike general time words like 以后 (yǐhòu), 事后 carries a subtle nuance of reflection, consequence, or evaluation: it’s commonly used when discussing what happens, is realized, or should be done once something is already over.

This term appears frequently in formal writing, news reports, legal contexts, and reflective speech — for example, describing how people respond to accidents, mistakes, or decisions after they unfold. It can also imply hindsight or delayed awareness ('only afterwards did we realize...'). While it may occasionally appear as a noun (e.g., 事后的处理, 'post-event handling'), its most frequent and natural use is adverbial, modifying verbs or entire clauses.