bec et ongles

listen to the pronunciation of bec et ongles
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tooth and nail
Viciously; with all one’s strength or power; without holding back

For a century, the two families fought tooth and nail over control of the land.

with force and ferocity; "she fought tooth and nail
With every available resource; with unrelenting effort: "Bureaucrats would correctly see this as a curb on their power and would fight tooth and nail against it" (George R. Packard)
in every way, by all means
with force and ferocity; "she fought tooth and nail"