expression, i-adjective
frail; physically weak; in poor health
Describes a person whose body is constitutionally weak or prone to illness. Often used as a prenominal modifier (体の弱い人).
彼は体の弱い子供だった。
He was a frail child.
体の弱い人は無理をしないでください。
People in poor health should not overexert themselves.
虚弱 is a more formal, medical term for constitutional weakness, while 体の弱い is a common descriptive phrase.
病弱 emphasizes being sickly or prone to illness, often used in formal contexts, whereas 体の弱い is a softer, everyday expression.
A phrase composed of 体 (body) + の (possessive particle) + 弱い (weak). The exact origin is transparent; it is a standard descriptive expression.