intransitive verb
Definition: To become weaker or less energetic; to lose strength or enthusiasm.
Example: After a long day, my energy began to flag.
noun
Definition: A piece of cloth, often rectangular, that has a unique design and color, used to represent a country, organization, or signal something.
Example: The country raised its flag during the ceremony.
transitive verb
Definition: To mark something with a flag for identification or to signal something, such as stopping a vehicle.
Example: The officer used a bright red flag to flag the car to stop.