Origin: Germanic Old English suffix
Weakness has 6 different meanings across 1 category:
powerlessness revealed by an inability to act
"in spite of their weakness the group remains active"
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"
a penchant for something even though it might not be good for you
"he has a weakness for chocolate"
The condition of being weak.
"The sudden weakness in his legs made it difficult to stand up after running the race."
In plain English: A weakness is something you are not very good at doing or an area where your character falls short.
"He admitted that his biggest weakness was getting nervous during public speaking."
The word weakness comes from the Old English wācnes, which also meant "weakness." It entered Middle English as a combination of the root for being feeble and the suffix indicating a state or quality.