Is it permissible to describe a human being as a "rational animal," and is a father to blame if he calls his son an "animal," relying on this description?

"Man is a rational animal" means that man is living and thinking, so the word "animal" here refers to life. However, since the word has become used as an insult and a curse in common parlance, it is not permissible to describe a human being with it, because cursing is forbidden by Islamic law. The father must repent from using it, and the son must advise his father kindly.