In the English language there are many expressions with the word ‘dog’. There are many dog-related expressions which show that the dog is not a favourite animal. For example, when we say that a person leads a dog’s life we mean that the person has an unhappy existence and leads an unpleasant life.
Look at this example: Some people are forced to lead a dog’s life after marriage.
People are compared to dogs in good as well as bad ways. A person who is judged as unreliable or disgusting is called a ‘dirty dog’ and an important person is called a big dog.
People who are insensitive or unkind can be described as meaner than a junkyard dog. A junkyard is a place where people throw away things they no longer want. Mean dogs are often used to guard a property and they bark or attack people who try to enter the property.
The idiomatic expression ‘Better be the head of a dog than the tail of a lion’ means that it is better to be the leader of a less prestigious group than to be a subordinate in a more prestigious one.
In a dog-eat-dog world, there is unhealthy and ruthless competition and people try to achieve success by all means. If a situation is dog eat dog, people follow unethical ways to become successful.
If you work like a dog, you work very hard. If you continue to work like a dog, you become dog-tired which means extremely tired.
The idiom ‘go to the dogs’ means ‘to decline or come to a bad end’. The phrase was first used by Thomas Copper in 1565 when food that was not suitable for human consumption was thrown to the dogs.
A hot dog is something pleasant you say when you are pleased with something. It also refers to a person who makes fast skillful movements in sports.
The expression every dog has its day means that every person enjoys a successful period during his or her life. If you are in the doghouse, someone is annoyed with you and shows their disapproval.
The phrase ‘to let sleeping dogs lie’ means not to invite trouble or to leave something undisturbed if it might cause trouble.
The reason a dog has so many friends is that he wags his tail instead of his tongue — Anonymous
— rayanal@yahoo.co.uk