underweight
US
UK underweight adj: (too thin)
SC 低于标准重量的 dī yú biāo zhǔn zhòng liàng de
SC 过轻的 dī yú biāo zhǔn zhòng liàng de，guò qīng de
SC 过瘦的 dī yú biāo zhǔn zhòng liàng de，guò shòu de
Ben had not been eating properly, so he was underweight.