Okay, the user wants me to translate "plain-looking" into Simplified Chinese. Let me think about the correct term here. "Plain-looking" usually means someone who isn't attractive or doesn't stand out in appearance. In Chinese, the common translation for this is "相貌平平" which literally means "ordinary appearance." I should check if there's any other possible translation, but I think "相貌平平" is the most accurate and commonly used. Also, the user specified to provide only the translation without any explanations, so I just need to output that term. No need to add anything else.