Russian

• быдло - bydlo ['bɨdlɐ] - roughly means 'cattle' (borrowed from the Polish word 'bydło', very popular on our chans)
• петух - petukh [pʲe'tux] - an abused prisoner, though often designates every gay (enjoy homophobic Russia); similar with пидор (see below)
• хуй, хер - khuj [xuj], kher [xʲer] - a dick (the former root is much more common)

  * хуёвый, херовый - khujovyj [xu'jovɨj], kherovyj [xʲɛ'rovɨj] - adj.: very bad, miserable, faulty
  * хуёво, херово - khujovo [xu'jovo], kherovo [xʲɛ'rovo] - adv.: very bad, miserably
  * хуйня, херня - khujnja [xuj'nʲa], khernja [xʲernʲa] - bullshit; something not worth attention
  * похуй - pokhuj ['poxuj] - interj.: means the speaker doesn't give a fuck
  * хуесос - khujesos ['xujəsos] - a dick sucker

• ебать - yebat' [je'batʲ] - to fuck

  * ебать! - interj.: God damn it!
  * ёбаный - yobannyj ['jobanɨj] - adj.: fucking
  * ебля - yeblja ['jeblʲɐ] - a fuck

• сосать - sosat' [sɐ'satʲ] - to suck (a dick)

  * соси - sosi [sɐ'sʲi] - imper. 2nd pers. sing.;
   e.g.: Соси хуй, быдло - literally, 'Suck the dick, cattle!'    (I can't translate it properly, but it's very offensive,    though its usage is restricted by Russian chans, almost    exclusively ex2ch.so)

• шлюха, блядь - shljukha ['ʂlʲuxʲɐ], bljad' [blʲætʲ] - 'a whore' and 'a slut' respectively
• мудак - mudak [mu'dak] - a moron, an idiot, an asshole etc
• пидор - pidor ['pʲidɐr] - a faggot, a queer
• пизда, пиздень - pizda [pʲiz'da], pizden' [pʲiz'dʲenʲ] - a pussy, a cunt
• жопа - zhopa ['ʐopɐ] - buttocks, an ass

  * жополиз - zhopoliz [.ʐopɐ'lʲis] - a lickspittle, a bootlicker

• залупа - zalupa [zɐ'lupɐ] - the head of a dick, a glans
• чмо - chmo [tɕmo] - a sissy not capable of standing up for himself
• дрищ, дрыщ - drisch [driɕ], drysch [drɨɕ] - a teen or young man physically not developed; often cognate with чмо
• лох - lokh [lox] - an oaf, a dupe

May continue.