If something is A-1, it is very good, or a person is completely healthy. You might hear “the car is in A-1 condition” (it works perfectly) or, in older speech, “I’m feeling A-1” (I feel very well). It sounds a little old-fashioned now; many people would just say “excellent” or “in great shape,” but you still meet it in stories, in ads that want a solid “top quality” feel, and in the set phrase “A-1 condition.” It comes from an old rating used by Lloyd’s of London for ships they insured: A1 was the top mark, meaning the ship was in the best class. From there, people started using A-1 for anything first-rate. It is first written this way in the 1830s. This is not the British road called the A1.