weightless

a light fabric that feels almost weightless几乎没有重量的轻薄织物

She floated in the pool, weightless.她轻飘飘地浮在泳池里。

The astronauts are living in a weightless environment. [=an environment in which people and things float because they are not affected in the usual way by gravity]航天员们生活在失重的环境里。