мудак

мудак is a Russian vulgar insult for a person regarded as stupid, unpleasant, inconsiderate, or contemptible.

• Depending on tone and context, it can mean “jerk,” “idiot,” “asshole,” or “douchebag.”
• “Jerk” is usually the safest English equivalent; “asshole” is closer in strength and vulgarity.
• It is masculine in grammatical form. A common feminine counterpart is мудáчка (mudáchka), though usage and tone vary.

Related expressions:

• идиот — idiot
• придурок — moron / dumbass
• козёл — jerk / asshole (literally, “goat”)
• урод — freak / asshole; can be especially harsh
• мудачок — “little jerk”; sometimes teasing, sometimes insulting

Background: The word has an old vulgar origin connected with a crude anatomical term. In modern Russian, it is commonly used as a general insult rather than literally.

Examples:

1. Он опять опоздал и никого не предупредил — ну и мудак.
   “He was late again and didn’t warn anyone—what a jerk.”
2. Не будь мудаком, помоги ей донести сумки.
   “Don’t be an asshole; help her carry the bags.”
3. Этот мудак занял два парковочных места.
   “That jerk took up two parking spaces.”
4. Я думал, он просто шутит, но он повёл себя как мудак.
   “I thought he was only joking, but he acted like an asshole.”
5. Мы помирились, хотя вчера я назвал его мудаком.
   “We made up, although yesterday I called him a jerk.”