The English language is a joy to behold, but a beast to learn. In addition to its numerous irregularities, there's a plethora of phrases and idioms that seem to make no sense to non-native speakers.
Here are the origin stories of common phrases you might not have known; explaining these is a fun ways to connect with new people--say, at a networking event. You end up looking smart but entertaining at the same time:
1. To turn a blind eye
Meaning: To know something is true but refuse to acknowledge it
Origin: Horatio Nelson was a skilled British maritime officer who was also blind in one eye. In 1801, he led a naval attack in the Battle of Copenhagen. When his partner in the battle, Admiral Sir Hyde Parker, communicated via flags that he needed to retreat, Nelson didn't want to acknowledge it. So he turned to a fellow officer, lifted the telescope to his blind eye, and said he "didn't see any signal."
He won the battle.
2. To spill the beans
Meaning: To reveal a secret
Origin: This is likely drawn from the ancient Greek process of voting, where votes were cast by placing one of two different colored beans in a vase (usually a white bean meant yes, and a black/brown one meant no).
If someone literally spilled the beans, the election results would be revealed.
3. Straight from the horse's mouth
Meaning: Getting info directly from the source
Origin: In the 1900s, savvy horse buyers could determine a horse's age by looking at its teeth. It was the most reliable way to know whether you were getting a good deal or not (as opposed to speaking with the seller).
4. To pull someone's leg
Meaning: To tease someone (often by lying in a joking fashion)
Origin: This has somewhat of a darker origin; thieves used to pull the legs of victims to trip them before robbing them.
5. Feeling under the weather
Meaning: To feel sick
Origin: When a sailor felt ill he often went belowdecks, and specifically under the bow (the front of the boat). The idea was to gain protection from the bad weather above (rain, lightning, swells, etc.). Thus a sick sailor was described as being "under the weather."
6. Hands down
Meaning: Definitely; absolutely
Origin: In the 1800s, horse racing was an intensely popular sport. When a jockey won "hands down" it meant he was so far ahead he was able to remove his hands from the reins and still win.
7. To fly off the handle
Meaning: To become enraged suddenly
Origin: In the 1800s, some poorly-made axes would literally themselves detach from handles, sending them flying. This would be not only dangerous, but very annoying for the person wielding it.
8. Sleep tight
Meaning: Sleep well
Origin: This likely stems from the days when mattresses were supported by ropes. Telling someone to sleep tight meant you hoped the ropes were pulled tight, which would mean a well-supported bed for them overnight.
9. To get someone's goat
Meaning: To annoy someone
Origin: Another from the world of horse racing: jockeys and others who cared for horses often put goats in stables to help horses relax and feel a sense of companionship (horses get lonely just like humans).
Competitors would remove the goat from the stables of rivals in the hopes of spooking the horse and having it lose the race.
10. To pull out all the stops
Meaning: To do everything in your power to make something succeed
Origin: The musical instrument the organ, often played in churches, has "stops" within it. Stops are knobs near the keyboard, which the player uses to select different sounds or timbres. When you pull out all the stops, it allows the organ to play to its fullest capacity (as loudly as possible).
11. Armed to the teeth
Meaning: to be completely ready for battle
Origin: Ever seen a pirate movie where they're carrying a gun between their teeth? When you've got weapons everywhere you can fit them on your person, the only other place to put the last one is between your teeth.
12. To kick the bucket
Meaning: Someone has died
Origin: Another dark one: when people used to hang themselves, they'd use a bucket to get up high enough to tie the rope over a rafter; when they were ready, they'd kick the bucket to begin the strangulation process.
Interestingly, this phrase has equivalents in other languages. In Ukranian it's "to cut the oak" (that you'll need for the coffin); in German, it's "to look at radishes from below" (like our "six feet under"); and in Swedish, it's "to take the sign down" (i.e. you'd hung out a shingle for your business on the main street, and now you'd take the sign down).
13. It's raining cats and dogs
Meaning: To rain very hard
This is my personal favorite. In Britain in the 1500s, houses had thatched roofs, which was really just a bunch of straw piled up on itself (no wood below). When it was cold and gray--which is at least half the year in the UK--animals like cats and small dogs would huddle in the straw of the roofs for warmth.
When it rained particularly hard, some of these animals would slip off the straw and wash into the gutters. Thus people started to say, "It's raining cats and dogs!" to refer to particularly heavy rain.