筋きん肉にくバカ

noun

musclehead; gym rat; person obsessed with building muscle

Colloquial, often mildly derogatory term for someone who prioritizes muscle training above all else, sometimes implying a lack of intellectual pursuits.

• 彼かれは一いち日にち中じゅうジムにいる筋きん肉にくバカだ。

  He's a musclehead who spends all day at the gym.

• 筋きん肉にくバカって言いわれるけど、健けん康こうのためにやってるんだ。

  People call me a gym rat, but I do it for my health.