"Breed in the bone" refers to something that is an innate characteristic or tendency in a person or animal. Some synonyms for this phrase include inherent, intrinsic, inborn, natural, innate, and ingrained. These words all convey the idea of something being a part of one's nature or being. Other related terms might include predisposition, proclivity, and disposition. Whether applied to human or animal behavior, "breed in the bone" suggests that certain traits are hard-wired and difficult (if not impossible) to change. Understanding what is "bred in the bone" can be helpful in predicting behaviors and tendencies, and adapting to them accordingly.