feeble-minded child; slow learner; poor student
Dated and potentially offensive term for a child with intellectual disability or very low academic performance. Modern usage is rare and often replaced by more respectful language.
In old educational settings, the term '低能児' was sometimes used.
彼は学校で低能児扱いされていたが、実は学習障害があっただけだ。
He was treated as a slow learner at school, but actually he just had a learning disability.
Standard kanji spelling.
Irregular kanji usage; 脳 is not standard here.
Compound of 低能 (low intelligence) and 児 (child). The exact historical origin is uncertain, but it reflects older, now-discouraged terminology for intellectual disability.