He plausibly explained his lateness, but his coworkers weren't fully convinced.

plausibly 是副词，由形容词 plausible（看似可信的）加上副词后缀 -ly 构成。plausible 来自拉丁语 plausibilis（值得鼓掌的），引申为"看似合理的、可信的"。 plausibly 表示"以看似合理/可信的方式"，常用来描述虽然听起来合理但可能不完全真实的情况。