In law, a warrant is a kind of legal authority giving by court to officers of the law to make a search of a person's property(which is known as the search warrant) or to arrest such person(which is known as the arrest warrant) if the person or Individual is found or suspected to have done or committed crime(s).
When an officer of the law search a person's property without a search warrant, the officer is breaking the Fourth Amendment's warrant requirement. But, in some cases, warrant is not needed if there is a probable reason for the police to search.
