Quality of being weak
fragility, weakness, debility, delicacy, infirmity, feebleness, decrepitude, daintiness, puniness, slightness, frangibility, susceptibility, brittleness, softness, flaccidity, unsubstantiality, flimsiness, limpness, shakiness, wobbliness, rustiness.
Antonyms strength*, indestructibility, firmness.
A moral or social weakness
The condition of being infirm or physically weak:debility, decrepitude, delicacy, delicateness, feebleness, flimsiness, fragileness, fragility, frailness, infirmity, insubstantiality, puniness, unsoundness, unsubstantiality, weakliness, weakness. See strong
An imperfection of character:failing, fault, foible, infirmity, shortcoming, weakness, weak point. See better, help