1. 司线员：line ball 触线球 | linesman 司线员 | net-cord judge 球网裁判员

2. 边线裁判：referee 裁判 | linesman 边线裁判 | champion 冠军

3. linesman的反义词

3. 视线员：let 发球时球触网 | linesman 视线员 | mental skills 心理状态

1. （足球、网球等运动中的）边线裁判员，巡边员，司线员
    A linesman is an official who assists the referee or umpire in games such as football and tennis by indicating when the ball goes over the lines around the edge of the field or court.

danci.edu.pub

1. a person who installs or repairs electrical or telephone lines

    Synonym: electricianlineman

2. official (in tennis, soccer, football, etc.) who assists the referee in some way (especially by watching for out of bounds or offside)