I think this is specific to my own neck of the woods, but the words "pija" and "verga". It can be used in a variety of different contexts and will mean anything between the bee's knees to absolute shit.
For example, "la mera pija/verga", literally "the very dick", means "the best"; while "la pija/verga" m, literally "the dick", means "the absolute fucking worst/incapable/incompetent". "Pijin" means rave, "pijeada/verguiada" means either a scuffle that ended with one side getting beaten very badly, or something that is very hard to do.
An example of the last one: "Darle pija a Malenia, Blade of Miquella, es pijeado", meaning "To beat Malenia, Blade of Miquella, is hard".
... Lots of phallic turns of phrase. But its usage probably isn't so different to the versatility of the word "fuck" in the english language.
недоперепил: недо - not quite, пере - overdid, пил - drank. Sounds weird due to opposing suffixes, basically means "haven't drunk enough to get completely wasted", in my circles we use it to describe displeasure when the alcohol runs dry on events we've set to get wasted all along.
опердень: Due to how it's only used in professional circles and how language is structured, someone hearing it for the first time might think it's a word rooted from "пердеть" (to fart), and based on the suffixes assume it relates to some kind of creature that farts (or get farted) all over. But it's actually a shorthand for Операционный День (processing day) which is how finance guys call their banking software as it basically replaced said processing day in their work.
Same for "опсос" - sounds like "someone who sucks all over something" but is just a shorthand for "оператор сотовой связи" - phone service provider.
Klabusterbeeren
Klabusterbeeren are "berries" out of cotton and hair, which you can only harvest from your ass crack.
Also known as Winterkirschen (winter cherries).
It is - though it may be fair to consider it jargon. It is a word that explicitly means "Can be set aflame" as chosen by people working with hazardous materials.