微笑(wēi xiào) - smile; to smile in Mandarin

微笑 (wēi xiào) is a smile, and to smile. The 微 is the same one as in 微波 for microwave and 微小 for tiny, so the word carries its own definition: the small, quiet version of a laugh, made with the face and not the voice.

It works as a verb (她微笑了) and as a noun (一个温暖的微笑), and it pairs naturally with 着 to describe a manner: 微笑着回答, answering with a smile. That 着 construction is one of the tidiest ways to add texture to a sentence in Mandarin.

The trap is that plain 笑 already covers smiling as well as laughing, and in ordinary speech it is what people reach for. 她笑了 is the neutral she smiled or she laughed, sorted out by context. 微笑 is a shade more literary and always silent, so a character who 微笑 in a novel is not making a sound. Do not use it for laughing out loud; that is 大笑 or 笑出声.