What does tooth and nail mean?

"Tooth and nail" is an English idiom that means using all of one's strength and effort to do something. It is derived from the old English words "tooth" and "nail," which were used to refer to the two hardest and sharpest parts of the human body. When someone is described as fighting "tooth and nail," it means that they are putting forth their utmost effort and determination to achieve their goal. The phrase can be used in both positive and negative contexts, depending on the situation. For example, it could be used to describe an athlete who is giving their all to win a race, or a student who is studying hard to get good grades. In either case, "tooth and nail" conveys the idea of someone who is not willing to give up without a fight.