1. A young cow that has not yet given birth: This is the most common and neutral definition. It's often used in agricultural contexts.
2. A large, heavy-set woman: This usage is considered offensive and derogatory, as it implies that the woman is unattractive and undesirable.
It's important to be aware of the negative connotation this word carries when used to refer to a woman.
Therefore, it's best to avoid using "heffer" altogether, especially when referring to a person. If you're looking for a neutral term for a young cow, simply use "cow" or "young cow."