Castellano (Spanish) is famous for the ruggedness (and frequency) of its swearwords. But in respect of one particular word, it can't hold a candle to Gallego (Galician).
In Spanish, the word is Carajo and in Galician it's Carallo. Here's how it's described in a document I have in front of me:-
CARALLO: Pronounced smoothly and clearly, without emphasis or stress, it means the male member.
!!!CARALLO!!!: As an exclamation, it can indicate astonishment, admiration, and, especially, assent.
An on-line dictionary translates Carajo! as Fuck! Damn it! (Very informal).
And Google Translate is very specific with Carallo:- Cock.
These are the examples of common (!) usage among Gallego speakers given by said document:-
Carallazo - Blow. Annoyance.
Carallada - Drinking spree. Binge.
Carallán - Joker
Caralludo - Denotes quality
Escarallado - Broken. Dislocated.
Escarallación -Peak, height.
Escarallar - To damage. Dying with laughter.
But [says the document] the variety and richness of the meanings of Carallo are almost limitless, given that it's used to both praise and denigrate. To say something is good and to say quite the opposite. It can also express tiredness, resignation, amusement and an infinity of states of mind, depending on the context. Here's some examples[all in Gallego]:-
Resignation: Ay que carallo! [Ay, what a cock]
Joke: Bueno, carallo bueno! [Good, cock. Good]
Rudeness - Vai o carallo! [Go to cock]
Enquiry - Que carallo e iso! [What the cock is that?]
Contrariness - Tócache o carallo! [Touch your cock]
Offence - Iste carallo é parvo! [Your prick is a fool!]
Temperance - Cámate . . . carallo! [Calm down, . . . prick]
Threatening - Ven . . . carallo . . . Ven! [Come on, prick. Come on!]
Denial - Non carallo. Non!
Rotund denial - Nin carallo nin nada![Neither prick nor nothing!]
Oath making - Me cago no carallo! [I shit on my prick]
Anger - Me cago no carallo . . . carallo [I shit on my prick . . . prick]
Praise - É un home de carallo [He's a man of prick]
Doubt - O carallo vintenove! [The 29th prick]
Strangeness - Pero . . . Que carallo pasa? [But . . . What the prick is happening?]
Contempt - Pásame por debaixo do carallo! [It passes me below the prick! (?)]
Animation - Dalle, carallo. Dalle. [Go for it, prick. Go for it!]
Whimsy - Salíume de carallo! [????]
Evaluation - Non vale un carallo! [It's not worth a prick]
Fatality - Ten carallo a cousa! [Have prick the thing! (???)]
Frustration - Xa estou o carallo! [Now I've had it up to my prick]
Meteorology - Fai un tempo de carallo! [It's prick weather!]
Distance . No quinto carallo [In the 5th prick]
On many occasions, it's used as a conversational catchphrase or as a wildcard in a long phrase or in difficult situations:-
Entón, chegou Pepiño e un servidor díxolle: Carallo, Pepiño. ¿Que carallo fas aquí?
Then Pepiño arrived and a waiter said to him: Prick, Pepiño, what the prick are you doing here?
To finish, and as a concession to the rich and flourishing literature of South America, here's a fine phrase: MANDA CARALLO NA HABANA!!, which was apparently uttered by Christopher Columbus himself, when the the Catholic Kings: LO MANDARON AL CARALLO! [Sent him to prick].
Finally . . . Here's a few phrases from a Spanish dictionary:-
Me importa un carajo - I couldn't give a shit
Irse al carajo - To go down the tubes
¡Vete al carajo! - Go to hell!
Needless to say, I welcome any and all additions and corrections from Galician and Spanish readers. Or even from foreigners who undestand these things better than I do. Dwight, for example. Even Peter. But not that bloody carallo Alfie Mittington!