Some more little words/idiomatic expressions you can use to sound more fluent
el caos = chaos / mess
Though it is usually "chaos", el caos can also refer to "a mess", like saying someone's room is un caos is like calling it a "pigsty" in English
el vaíven = ups and downs, ebb and flow
This is now treated as a single noun, but the expression itself is from va y viene "comes and goes", which got shortened over time. This expression is used the way we say "ups and downs" in English, or just to describe the "flow" of things, particularly water or ocean waves
cualquier / cualquiera
This one requires a bit of grammatical explanation + the additional idiomatic meaning. In general the word is cualquiera which means "any" as a determiner, so by itself it can read as "any one (of something)" - the exact translation is something like "whichever" or to keep the meaning of -quiera it might be more correct to say "whichsoever" as a subjunctive modifier... but in practice it's best understood as "any which one" from a group.
This is different from cada "each", cualquiera refers to one in particular from a group
Grammatically used as a determiner, cualquiera can be a bit weird; when placed in front of a noun, however, it turns to cualquier; as in... cualquier persona "any person" rather than cada persona "each person"
Now, that being said we get into the idiomatic use of it. If you place cualquiera AFTER the noun, it takes on an additional meaning of "any old", meaning "ordinary", sometimes meaning "cheap" or "replaceable"
In other words... cualquier persona is "any person", and una persona cualquiera "an ordinary person / any old person" something similar to "everyman"; when said of women in particular una mujer cualquiera or una cualquiera can mean "hussy" or really "a woman of little value that can be found anywhere", or sometimes it's the equivalent of calling someone a "rando" or "random person"
al azar = randomly, by chance
This one just requires additional explanation. The general word for "luck" is la suerte or la casualidad
But el azar means something like "blind luck" or "chance" - things happen al azar "by chance" or "randomly", but when someone is lucky it's tener suerte
When something is "random" as an adjective it's normally aleatorio/a
The idea behind el azar is related to the uncertainty of luck and chance, or the dangers or consequences unpredictability. Its etymology is Arabic, while the other words tend to be Latin. In fact la suerte is related to "fate" in the sense of "drawing lots" [sortear or el sorteo is something like "a raffle" or "pulling names out of a hat" or "lots"], but el azar comes from the Arabic word el azahar which is "orange blossom" - the idea being that very old games of dice in the (ancient) Middle East were played with dice that had specific images on them and one was an orange blossom
Today el azar "chance" and al azar "by chance" or "at random" have a more unpredictable and potentially negative connotation, where there's more emphasis on consequences and so it's best understood as "randomness"; that being said it did eventually work its way into English (by way of French) as the word "hazard" - in the way that it came from dice games in the Arabic-speaking world, so something that brought out a potential obstacle... and in English we also say "to hazard a guess" drawing on the idea of happenstance and blind luck or randomness
cursi = "tacky", "corny", "cutesy", "sappy / overly sweet or sentimental"
This is usually said in the context of "in bad taste" or when something is "pedantic", or when jokes/comments are "corny", or when decorations are "kitschy" or "tacky"... it's general "bad taste". But you also see it a lot with things that are so sentimental and so cute that it becomes "cutesy" or "quaint"
cursi is that feeling you get when you, an adult, watch a children's show and everything is excessively love and friendship... cursi is the feeling behind hearing a dad joke. It's that vibe
menos mal = "at least", "just as well"
Literally "less bad", but people say menos mal the way we say "at least" or "thank goodness" or "it's a good thing" etc. when try and mitigate a potentially bad thing
Like menos mal que llegó al fin "at least he/she got there eventually", or menos mal que tengo a mis amigos "thankfully I have my friends"
It can also be a complete sentence, the same way people say "it's just as well" or "thank goodness" etc.
regular = normal / "so-so"
In general, regular is a cognate as "regular", or "normal", but when people ask "how are you?" you can reply as regular to mean "so-so" - not good and not bad. Some people say más o menos, but it's very common to say regular ... there are a handful of other regional expressions people use like así así or ni fu ni fa which I associate more with Spain, but it's something good to know just in case
ahogarse en un vaso de agua = "to make a mountain out of a molehill", "to be dramatic"
One of my favorites, this literally means "to drown in a glass of water", but it's commonly used as a command - no te ahogues en un vaso de agua "don't be so dramatic" or "don't blow things out of proportion"
ni = "not", "not even" / strong negation word
This one requires some extra explanation. The word ni is one of the negation words [nada, nadie, no, nunca, ningún/ninguno..... most negation words (but not all) start with N like that] - it's a word that implies "no" or "not" in some way. And in general you'll see ni used as the negative version of o "or"; in other words ni can come out as "neither/nor" while o can be "either/or"
But, in other ways ni can be used as an idiomatic strong "no", when places in front of certain expressions. These are ones like ni hablar "no way" [lit. "not/neither speaking"] or ni modo "no way" [lit. "no/neither way/mode"], or ni en sueños which is "not even in dreams" but comes out like "in your dreams" or "absolutely not"
More than that, ni can be used in some expressions like ni siquiera "not even (something)", or ni que "it's not like". As an example, ni siquiera me llaman "they don't even call me", and ni que me llaman "it's not like they call me". Another expression to know is that ni que decir which is "it goes without saying" - an opposition to hay que decir "it should be said"
el príncipe azul = "knight in shining armor", "prince charming"
This literally means "blue prince", but it's understood as a stereotypical hero. The suggested etymology is that azul "blue" comes from the idea of "blue blood" and descendants of nobility - although it has also been suggested that the color blue is associated with the main character in a Romanian fairytale/folk hero; the story in Spanish is el infante hermoso which is like "the handsome (noble) son/child"
Should also mention connected to this, some people use it as "prince charming" like a hero archetype, but when talking about romantic suitors the word is sometimes el galán which is something between "leading male archetype" and "male romantic suitor", where el galán can also take on the meaning of Don Juan
la quimera = "pipe dream", an unrealistic fantasy / "chimera"
This is largely going to depend on if you're talking about the everyday vs a specific fantasy context
In a fantasy context, la quimera is usually used as "chimera" the mythical creature, particularly in Greek mythology or in things related to alchemy
For general Spanish though la quimera refers to an unrealistic dream or fantasy, like a "pipe dream"... a kind of idealistic fantasy that is unattainable
I was also going to mention this one because it's not an expression exactly, but el azufre is literally "sulfur", but it also comes out as "brimstone" in some contexts - el fuego y azufre is "fire and brimstone"
I also wanted to include this fun set of regionalisms here
The general word for "to work" is trabajar and that is universally understood
Other words to know are very regional
currar = to work [Spain]
This one is mostly related to Spain, where el curro can be another word for "work" like a job. Be careful with this one in South America; probably because of a difference in meaning for Brazilian Portuguese, some Rioplatense interpretations of currar come out as it being shady/illegal work
Also another word I associate with Spain is el tajo for "work" where normally el tajo is "a chop/cut", but ir al tajo is "going to work" probably because el tajo can also mean "the site/place" in some places
laburar = to work [South America]
I associate this mostly with South America, but laburar is "to work", coming from the idea of "labor"
chambear = to work [Central America]
This one I associate mostly with Mexico, but it can be Costa Rica, Honduras, and Guatemala too. The word la chamba is the root word and for Central America it means "work" - for Spain, la chamba comes out as like "a fluke" as in very good luck that's totally random, which I believe is related to old Galician and has made its way to Catalan as well... otherwise la chamba can be an architectural/civil engineering word for a "trench" in some places in Spain but it's unrelated as far as I know
