very cold, with a thin layer of white ice covering everything

The frosty air stung my cheeks. 冰冷的空气刺痛了我的双颊。

It was a cold and frosty morning. 那是个天寒地冻的早晨。

If someone, or someone's behaviour, is frosty, they are unfriendly and not welcoming.

He gave me a frosty look. 他冷冷地看了我一眼。

The chairperson's plan received a frosty reception from the committee. 委员会对主席的计划反应冷淡。