Idioms are figures of speech that become fixed in a language. Usually, an idiom is figurative in modern contexts but once had a literal meaning. These literal meanings, or idiom origins, can help a learner of English to understand where a phrase originated.
1. Straight from the horse’s mouth
Meaning: getting information directly from the most reliable source
Origin: This one is said to come from the 1900s, when buyers could determine a horse’s age by examining its teeth. It’s also why you shouldn’t “look a gift horse in the mouth,” as inspecting a gift is considered bad etiquette.
2. Let the cat out of the bag
Meaning: To reveal a secret, unwittingly or otherwise
Origin: First seen in several London publications in the 1700s, its origin dates well before that and refers to a then-common street fraud. Market scamsters apparently attempted to replace pigs (valuable) with cats (not so much); if the cat was let out of the bag, the gig was up. That's related to why you don't want to buy "a pig in a poke" (i.e., a small bag): You might not be getting the real item.
3. Butter someone up
4. Pulling someone’s leg
Definition: Joking or fooling with someone.
Origin: To pull someone’s leg had much more sinister overtones when it first came in use. It was originally a method used by thieves to entrap their pedestrians and subsequently rob them. One thief would be assigned ‘tripper up’ duty, and would use different instruments to knock the person to the ground. Luckily, these days the saying is much more friendlier, though being on the end of a joke might not always be fun.
5. Wolf in sheep’s clothing
Meaning: someone who is pretending to be something they are not, usually to the detriment of others
Origin: This one’s attributed to the Bible (Matthew 7:15). The Bible also gave us “rise and shine” (Isaiah 60:1), “seeing eye to eye” (Isaiah 62:8), and a “broken heart” (Psalm 69:20).
6. Hands down
Meaning: without a lot of effort
Origin: Winning “hands down” once referred to 19th-century horseracing, when a jockey could remove his hands from the reins and still win the race because he was so far ahead.
7. Riding shotgun
Meaning: riding in the front seat of a vehicle next to the driver
8. Barking up the wrong tree
Origin: Likely referring to hunting, this saying explains when a dog would literally bark at the bottom of the wrong tree after the
prey in question moved to the next branch.
9. Flying off the handle
Origin: This one is said to come from poorly made axes of the 1800s that would literally detach from the handle. Yikes!
10. Cost an arm and a leg
Meaning: extremely expensive
Origin: The story goes that this phrase originated from 18th-century paintings, as famous people like George Washington would have their portraits done without certain limbs showing. Having limbs showing is said to have cost more.