To have made a great effort. The literal significance of being blue in the face is lack of oxygen, and indeed, this expression sometimes indicates that one has talked until one is breathless. But it also has been extended to other kinds of effort, as in “I tried to open that sardine can until I was blue in the face.” It was current in the mid-nineteenth century, when Anthony Trollope wrote, “You may talk to her till you’re both blue in the face” (The Small House at Allington, 1864).