Her opponent injured her ankle and had to withdraw from the match.

opponent 是名词，由前缀 op-（表示"反对、对抗"）和词根 -pon-（来自拉丁语，意为"放置"）加上后缀 -ent（表示"人"）组成，字面意思是"站在对立面的人"，即"对手、竞争者"。