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.
horse around: rough or noisy play
Example:
The lifeguard kicked out the boys who were horsing around on the diving board.
horse of a different color: something totally separate and different
Example:
You’re planning on going to State U. instead of Harvard? That’s really a horse of a different color.