(informal)a difficult situation from which there is no escape because you need to do one thing before doing a second, but you need to do the second thing before you can do the first进退维谷的局面
I can't get a job because I haven't got anywhere to live but I can't afford a place to live until I get a job—it's a catch-22 situation.我没有住所就找不到工作，但是没有工作就没钱租房子，这真是左右为难。