enemigo acérrimo

(n.) = arch enemy [archenemy], arch-rival [archrival], sworn enemy

Ex. The article 'The case of Charles Merrill Mount: the archivist's arch enemy' describes the theft of valuable letters and documents by Charles Merrill Mount.

Ex. The geneticist and arch-rival of the biometricians, Williams Bateson, was very critical of this work and interpreted this as Weldon's rejection of Mendelism.

Ex. I wouldn't quite call them our sworn enemies, any more than a mosquito is a human's sworn enemy.

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(n.) = arch enemy [archenemy], arch-rival [archrival], sworn enemy

Ex: The article 'The case of Charles Merrill Mount: the archivist's arch enemy' describes the theft of valuable letters and documents by Charles Merrill Mount.

Ex: The geneticist and arch-rival of the biometricians, Williams Bateson, was very critical of this work and interpreted this as Weldon's rejection of Mendelism.

Ex: I wouldn't quite call them our sworn enemies, any more than a mosquito is a human's sworn enemy.