Summary:

Tooth and nail is a colorful idiom, without reservation, but to fight with all one’s power and strength.  The phrase originally referred to battling an adversary and using one’s teeth and nails as weapons, involving biting with the teeth and scratching with the nails.

Article:

The phrase can be used in many variations:

Fight off a predator (you figure out what kind) tooth and nail

Defend (someone or something) tooth and nail

Try to improve or accomplish something tooth and nail

Oppose ( someone or something tooth and nail

Even with a positive connotation, I will fight my way to the top tooth and nail, using all my power and strength to accomplish my goals and be successful.

One’s performance or promotion

Striving for justice

Fight for illusions like climate change

Academic achievement

Political competition

Although it may sound corny, its history dates back to the late 1500s.