tooth and nail

adverb

1. with all one's resources or energy; fiercely.

   We fought tooth and nail but lost.

tooth and nail

1. To fight “tooth and nail” is to fight with the intensity and ferocity of a wild animal: “The resistance forces fought the invading troops tooth and nail.”

Word History and Origins

Origin of tooth and nail¹

First recorded in 1525–35

Example Sentences

Highlighting her record as education secretary, Phillipson said she had fought "tooth and nail" for policies like the expansion of free school meals.

From BBC

But according to Ms Skinner's lawyer, all the high-value complex claims are being fought "tooth and nail".

From BBC

“You come after our votes in California and we will fight you tooth and nail,” he said.

From Salon

Oil and gas companies are “fighting tooth and nail for what they see as their interests ... but it shouldn’t be the driver of our policy,” he said.

From Los Angeles Times

“Instead, they are paying a law firm to fight tooth and nail against obligations that are clear in the settlement agreement — and that a judge has affirmed they are in violation of.”

From Los Angeles Times