1. Stubborn or obstinate: This is the most common meaning. It refers to someone who is inflexible in their opinions and refuses to change their mind, even when presented with evidence to the contrary. They are often described as "thickheaded" or "bullheaded."
Example: "He's got a hard head and refuses to listen to any advice."
2. Someone who is intelligent or resourceful: This meaning is less common but still used, particularly in certain contexts. It refers to someone who is able to think critically and find solutions to problems, even difficult ones. They are often described as "smart" or "clever."
Example: "She has a hard head for business and always comes up with innovative ideas."
The meaning of "a hard head" will depend on the context in which it is used. If you are unsure of the meaning, it is always best to ask for clarification.