Longman Dictionary of Contemporary English - weakness

~ n 1 »PHYSICAL« the state of being physically weak  (weakness in the muscles) 2 »LACK OF DETERMINATION« lack of determination shown in someone's behaviour  (sign of weakness)  (Most people saw her sensitivity as a sign of weakness.) 3 »LACK OF POWER« lack of power and influence  (the weakness of the Trade Union movement in post-Thatcher Britain) 4 »CHARACTER/DESIGN ETC« a fault in someone's character or in a system, organization, design etc  (We spent two hours analyzing the team's strengths and weaknesses. | a structural weakness in the aircraft) 5 »IDEA, PLAN ETC« a part of something that can easily be attacked or criticized + in  (We finally found a weakness in their case.) 6 a weakness for sth if you have a weakness for something, you like it very much even though it may not be good for you  (Ryan's always had a weakness for fast cars.)