This is the 13308th most frequent Russian word.
мужские
"Мужские" means "men's" or "male" in English.
The word 'мужские' is used as an adjective meaning 'men's,' modifying the noun 'костюмов.'
В магазине есть новая коллекция мужских костюмов.
The store has a new collection of men's suits.
Here, 'мужском' (masculine form of 'мужские') indicates the gym is for men.
Тренировка прошла в мужском спортивном зале.
The training took place in the men's gym.
In this sentence, 'мужские' is used adjectivally to denote the gender of the voices, referring to them as male.