i-adjective
weak; frail; delicate; tender; unskilled; weak (wine)
Broadly describes lack of physical strength, fragility, delicacy, tenderness, lack of skill, or low intensity (e.g., weak alcohol).
彼は体が弱いので、よく風邪をひく。
He has a weak constitution, so he often catches colds.
This sake is weak, so it's easy to drink.
私は数学に弱い。
I'm weak in math.