Weakness

n. feebleness; drawback, disadvantage; defect; foible

Weakness may refer to: The opposite of strengthMuscle weaknessFatigue (medical)A "loophole" in a code or a software that can be exploited to gain access to a computer system or to make the software work in a way is wasn't intended to.
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Weakness a weak bodily state as expressed by reluctance to and difficulty in rising, a shuffling, disinclination to move and then only slowly, [more]Weakness - Community and Resources

Noun
1. a flaw or weak point; "he was quick to point out his wife's failings"
(synonym) failing
(hypernym) imperfection, imperfectness
(hyponym) insufficiency, inadequacy
2. powerlessness revealed by an inability to act; "in spite of their weakness the group remains highly active"
(synonym) helplessness, impuissance
(hypernym) powerlessness, impotence, impotency
3. the property of lacking physical or mental strength; liability to failure under pressure or stress or strain; "his weakness increased as he became older"; "the weakness of the span was overlooked until it collapsed"
(antonym) strength
(hypernym) property
(hyponym) adynamia
4. the condition of being financially weak; "the weakness of the dollar against the yen"
(antonym) strength
(hypernym) misfortune, bad luck, tough luck, ill luck
5. a penchant for something even though it might not be good for you; "he has a weakness for chocolate"
(hypernym) preference, penchant, predilection, taste

(n.)
The quality or state of being weak; want of strength or firmness; lack of vigor; want of resolution or of moral strength; feebleness.
  

(n.)
That which is a mark of lack of strength or resolution; a fault; a defect.