Antonyms for the phrase "regaining strength" include feebleness, debilitation, exhaustion, weakness, and frailty. These words describe conditions where one is not able to perform daily activities without difficulty, lacks energy, and is physically or emotionally drained. Feebleness connotes both physical weakness and lack of mental acuity. Debilitation refers to a state of reduced strength and vitality resulting from an illness, injury, or excessive fatigue. Weakness implies a state of vulnerability, inability to cope, and fragility. In contrast, the act of "regaining strength" suggests a process of physical and emotional renewal, recovery, and empowerment.