1. a professional boxer who weighs between 131 and 135 pounds

2. someone who is unimportant but cheeky and presumptuous

3. an amateur boxer who weighs no more than 132 pounds

4. a wrestler who weighs 139-154 pounds

1. weighing relatively little compared with another item or object of similar use;

   "a lightweight fabric"
   "lightweight wood"
   

2. having no importance or influence;

   "a lightweight intellect"
   

1.轻量的；轻质的；比通常重量轻的
Something that islightweight weighs less than most other things of the same type.

e.g. ...lightweight denim...
轻磅牛仔面料
e.g. The company manufactures a range of innovative light-weight cycles.
这家公司生产一系列的新型轻便自行车。

2.（拳击、柔道、赛艇等运动中的）轻量级
lightweight is a category in some sports, such as boxing, judo, or rowing, based on the weight of the athlete.

e.g. By the age of sixteen he was the juniorlightweight champion of Poland...
16岁时他已经是波兰的青少年组轻量级冠军。
e.g. He changed fromlightweight (under 71kg) to light middleweight (under 78kg).
他从轻量级（71公斤以下）转到了轻中量级（78公斤以下）。

3.无足轻重的人；无能的人
If you describe someone as alightweight, you are critical of them because you think that they are not very important or skilful in a particular area of activity.

e.g. Hill considered Sam alightweight, a real amateur.
希尔认为萨姆无足轻重，是个十足的生手。

1. 轻量化：SOAP 是一个轻量化(lightweight)的通讯协定. 为达到语意网的目的,采用的方式为使用本体定义同域所用到的知,这些知包含字汇和关系,本体以XML based 的方式表达以方网资源存取. 语意网中的本体(ontology)运用在网的资讯表达,

• Tastier than the lightweight singles of their past.

  出自：Melody Maker

• In the warmest weather our lightweight poplin suit maintains its..crisp appearance.

  出自：New Yorker