i-adjective
Describes a person, action, or thing that appears physically or emotionally weak, lacking strength or vitality. Often carries a nuance of pitifulness or delicacy. Can also describe faint light or sound.
彼は病気で弱々しい声で話した。
He spoke in a weak voice due to illness.
弱々しい日差しが窓から差し込んでいた。
Faint sunlight was coming through the window.