Meaning of “slug it out” - Learner’s Dictionary

slug it out

informal phrasal verb with slug us uk /slʌɡ/ verb [ T ] present participle slugging, past tense and past participle slugged informal

to fight, argue, or compete with someone until one person wins:

Federer and Nadal slugged it out for a place in the final.

(Definition of “slug it out” from the Cambridge Learner’s Dictionary © Cambridge University Press)