Describes a constitutionally weak body or health; often used in medical or formal descriptions of physical frailty. Can also refer to mental or moral weakness in literary contexts.
To improve a frail constitution through dietary therapy.
N5
弱い is a general i-adjective for weakness in any sense (body, mind, taste, etc.), while 虚弱 is a more formal term specifically for constitutional physical frailty.
脆弱 describes something fragile or vulnerable (often structures, systems, or defenses), whereas 虚弱 is used specifically for a person's frail physical constitution.
