trackie       
noun [ C ] UK uk/ˈtræk.i/ us/ˈtræk.i/
 (tracksuit的非正式叫法)(运动练习时或作便衣穿的)宽松暖和的衣裤;运动服
informal for tracksuit: a loose top and trousers, worn either by people who are training for a sport or exercising, or as informal clothing
  She wouldn't dream of leaving the house in a trackie and no make-up.
 Three men in trackie tops wandered down the street.
 He turned up in an old sweater and trackie bottoms (= trousers). 他穿着一件旧毛衣和运动裤出现了。 
 - More examples
- Have you seen my velour trackie?
- No denim, trackie bottoms or trainers are allowed in the bar.
- "Nice trackie there John," said Sam.