Lacking in quantity, quality, or strength; meagre, feeble, or insubstantial.
彼の説明は貧弱で、聞いてもよく分からなかった。
His explanation was poor and I couldn't understand it even after listening.
この店のメニューは種類が貧弱だ。
This restaurant's menu is meagre in variety.
貧弱な体つきでも、毎日運動すれば強くなる。
Even with a feeble build, you can get stronger if you exercise every day.