Weakness or debility — a state of reduced physical strength or vitality, often due to illness, aging, or prolonged strain.
長期入院で体が衰弱してしまった。
His body became weakened after a long hospitalization.
高齢で衰弱した祖母を介護している。
I'm caring for my elderly grandmother who has become weak.
栄養不良が続くと衰弱していくことがある。
Continued malnutrition can lead to progressive weakening.