If you are a foreigner visiting for the first time Mexico will quickly realize the great amount of jargon that exists in the vocabulary of the day to day.
Although initially I want to clarify that most jargon words appear as a deformation of the Spanish language and many of them may be vulgar or with a bad meaning. So, if you travel for business or professional situations it is not correct to use them much. Then, I write the most used and "educated" words that if you say them with Mexican friends you will win their appreciation and it is even very likely that they will accept you with one of them.
1. ¡¿Qué onda?! / ¿Qué pasó?
Literally means: what wave?
But it means: What's up?
There are many counterparts for this expression depending on the group of people you are with, "¿Que paso?". It is another very common expression, something much more informal and maybe even vulgar is this other "¿Qué tranza?".
Literally "waves" means "waves ", but they are not waves in the sea. The etymology of the phrase is difficult to describe, but is thought to arise from the word vibrates. When you ask "¿Qué onda?", they are asking what vibes you have, what humor, what emotion to bring with you. That's why if you greet your new friends this way is common that Mexicans feel familiar to you. I think it is an expression widely used in most of Mexico's social strata.
2. "Esta cañón"
Literally means: "it's cannon"
But it means: "it's rough"
This is a very common expression when people encounter an activity that is very difficult to realize that is very slow or requires a lot of effort. We could put an example in which you are learning Spanish but you are very difficult then you say "I'm learning Spanish, but this cannon". In that expression you indicate that Spanish or any other languages is very difficult or it takes a lot of effort to learn it. In my case I would say "learning Chinese esta cañón".
Literally means: "Waters"
But it means: "Be careful!”
¡Aguas! It is a widespread way among Mexicans to say that you have to be careful about something, even the federal government has carried out health campaigns with this phrase: "Aguas with dengue" for example, a daily situation is when you want to cross a street, But the cars are still happening, you say "Aguas con los carros" it means "be careful with the cars". It is a very common phrase when you want the person to be careful about a certain issue.
It's means: "cool" "so nice"
This expression has no English translation, is used as a noun, is widespread among all strata of the Mexican Society, when you want to express that an object or a person is very nice, then we say: "Esta flor esta chida (This flower is great)" , "Esta casa esta chida (This house is cool)", "Ese viajes fue chido (That trip was cool)".
It is necessary to take into account that as a noun this expression has a gender that is to say for masculine nouns we say "Chido" and for feminine nouns we say "Chida". So the next time that someone ask you about how your trip was, you should say "Mi viaje a mexico estubo chido (My trip to Mexico was cool)".
5. "¡No manches!"
Literally means: "Don’t stain!"
It's means: "Unbelievable”
Usually we use this word to refer to something that surprises us a lot, something that is incredible, especially when someone has done a feat in life, or a situation that we have trouble believing as real.
For example, if a person says, "I learned Spanish in less than 1 year," a person who listened to this will usually say, "No manches."
Literally means: "Tell me"
This word is very common to hear it among Mexicans, with people living in small and medium towns. While it literally translates to "tell me", it has a deeper meaning: it is to be placed under the command of a superior person in hierarchy.
To understand this, it must be remembered that at some time Mexico was a Spanish colony where there were a large number of castes from Indians, mestizos, Creoles and Spaniards. So when someone did not correctly hear an order or his name had been named, they would say "¿Mande usted?" with a tone of questioning and also of reverence. That is why until nowadays it is educated to say to the children this word.
7. "Te crees muy muy"
Literally it means: "You think you're very, very"
It means: "You think you're a badass?"
This is a phrase with a humorous sense, nowadays it is said with intention to make the other person feel that it presumes a lot of what it has or what it is, and that irritates to the people that are to him around. For example, Someone who constantly presumes to be very intelligent or have many skills, someone could confront you and say "Asi con que te crees muy muy" to challenge them to demonstrate their skills.
It's the most common way to say "Really?" to friends. Although, you can also say this when someone has behaved very well with you.
For example: "Tu papa es la neta (Your dad is the best) " or "Esta fiesta es la neta (This party is the best)." It is also used to feed back information such as: if you say "Yesterday Susan accepted to be my girlfriend" a Mexican would say "¿Es neta?(really?)"
Literally understood as: "Little now"
It means: "Right now"
"Ahorita" if we take into account that it is very common to make a diminutive of things in Spanish (especially in Mexico), we will understand that the endings -ita -ito, as for example: gatito (Little cat), hermanita (Little Sister).
We will understand literally "ahorita" as "little now" a little now, but what really is trying to say right now, such as when they ask, When will you be ready? - "ahorita", when will we do the homework? - "ahorita". There are too many uses for this simple word. You just have to be careful because many people use this expression to say that something will be ready right now, but not actually at that very moment, and in fact one needs to wait a few minutes at a minimum, this expression is like right now but sometimes doesn't mean the same thing.
10. "Darle vuelo a la hilacha"
Literally it means: "Give flight to the lint"
It means: "to lead a life without shame and disordered"
This happens when you, one of your friends or relatives lead a life without modesty and disorderly, that is to say that they go from party to party, they drink too much alcohol among other things and that consequently will have something bad in the future. The thread is a thread that usually comes off a cloth, and it is well known that the loose threads can ruin a full fabric, that is why your friend "le da vuelo a la hilacha" is very sure to end badly.