Every Saturday I’ll give you a couple of idioms to learn. An idiom is a saying or phrase whose meaning cannot be taken from the literal meanings of the words.
dark horse: In an election, a dark horse candidate is one unexpectedly nominated, who previously had not been considered a likely choice.
Example:
Abraham Lincoln was a dark horse Republican candidate who became the 16th president of the United States.
dog-eat-dog: indicating all-out competition, fighting and doing whatever it takes to win or be successful; having a “kill or be killed” mentality in business or other competition.
Example:
Pressure to get into a top-name university results in dog-eat-dog competition and widespread cheating among some high school students.