[n] 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"
[n] powerlessness revealed by an inability to act; "in spite of their weakness the group remains highly active"
[n] a penchant for something even though it might not be good for you; "he has a weakness for chocolate"
[n] a flaw or weak point; "he was quick to point out his wife's failings"
[n] the condition of being financially weak; "the weakness of the dollar against the yen"