The term 'DOG'S WARNING' can be broken down into four crossword solutions: BARK (4 letters), GROWL (5 letters), SNARL (5 letters), and GRR (3 letters). A dog's BARK is a common warning sound, usually used to alert its owner of potential danger or to express excitement. A GROWL is a low, guttural sound that is often used to express aggression or displeasure. A SNARL is a more intense version of a GROWL, and is usually accompanied by bared teeth and a curled lip. Finally, a grr is a short, sharp sound that is often used to express anger or frustration. All of these sounds are warnings from a dog, and can indicate that it is feeling threatened or uncomfortable.