Meaning of “Noukin(脳筋)”
“Noukin(脳筋)” means simple and stupid.
“Noukin(脳筋)” is an abbreviation for “Noumiso(脳みそ) Made(まで) Kinniku(筋肉)”.
This is a slang.
“Noumiso(脳みそ)” means brain.
“Made(まで)” means also.
“Kinniku(筋肉)” means muscle.
So we use “Noukin(脳筋)” when we speak evil of muscular person. It means “His brain is also muscle, so that’s why he is simple and stupid.”
Some people have a bias against some people like this.
“Muscular person is simple and stupid”
“Big boobs person is stupid”
A: The macho is the team leader.
B: Wow, really?
A: He is so smart.
B: I thought he is “Noukin(脳筋)”