The phrase "attack dog" is often used to describe a canine trained to attack on command. However, there are several synonyms that can be used to describe such dogs. Some of these include guard dog, watch dog, protection dog, and police dog. While each of these terms refers to a dog that has been trained to provide protection, they may also have different connotations. For example, a police dog may be trained to assist law enforcement officers in apprehending suspects, while a protection dog is typically used to guard homes or businesses. Despite the nuances in meaning, these synonyms all share the overarching goal of providing a sense of security and protection for their owners.