Final answer:
The meaning of 'bad blood' is a term used to describe a long-standing feud or animosity between individuals or groups, not a medical condition.
Step-by-step explanation:
The term bad blood refers to animosity or ill will that has developed over time between individuals or groups. It is not related to an actual blood disorder or disease. This idiom is commonly used to describe situations where there is a history of feuding or negative relations between parties, often making any kind of cooperation or reconciliation difficult.