Here are a few options, depending on the nuance you want to emphasize:
* *usque ad mortem*: This translates to "even unto death," suggesting a fight to the bitter end. This emphasizes the desperation of the struggle.
* *cum omni vi*: This means "with all force" or "with all one's might." This highlights the intensity of the effort.
* *nihil timentes*: This translates to "fearing nothing," implying a bold and fearless fight.
* *acriter pugnans*: This means "fighting fiercely" which captures the essence of the idiom more directly.
The best choice will depend on the context. None perfectly capture the imagery of "tooth and nail," but these options convey the similar sense of a determined and aggressive struggle.