sleep rough 是习语，主要用于英国英语，《朗文英语联想活用词典》对它的解释是：a British expression meaning to sleep outside or in an empty building because you have no home or nowhere to stay. （因为没有家或没有住的地方而）睡在外面，露宿；睡在空房子里。例如：

The wanderer has to sleep rough. 这个流浪汉到处为家。

Jobless and penniless, he had to sleep rough in the fields for several months.他既无工作又无钱,只好在野外露宿数月。

Those who do not have relatives to return to are left to wander the streets and sleep rough. 举目无亲的人只好四处游荡，露宿街头。

It is hard to imagine what it is like to sleep rough at any time, but doubly so in the current freezing weather. 无论何时，露宿街头的滋味都是难以想象的，更何况是在现在这么冷的天气下。