I haven't checked the Word's Worth mailbag in a while … let's see what's in here … Here's a good question: "My neighbor keeps calling me пиндос. Is that good or bad?" It's good if you're a pony. But if you're an American— not so much.
Ah, here's an interesting one: "In the U.S. election campaign, politicians are constantly saying things that they regret the next day. They say, 'I misspoke.' What do Russian politicians say in those circumstances?"
Very interesting question. After an hour or so of searching on the Internet, I discovered that Russian politicians never misspeak. Not once, not ever. According to them — and their press secretaries — "Вы неправильно их поняли" (You misunderstood them). Nice perk of the job.
It is, of course, possible to admit to a verbal blunder in Russian, even if the men and (two) women at the top never do. The best word for this is оговориться. Мама оговорилась и назвала Людмилу Светланой (My mother misspoke and called Lyudmila Svetlana). Keep in mind that you have to be a bit careful with this verb. Sometimes it means to issue a kind of warning: Должна оговориться: исследование пока ещё не закончено, до выводов далеко (I have to warn you: the research isn't finished yet and we are a long way from drawing conclusions). Or it can mean to clarify: Я любил эту девушку; но спешу оговориться: я любил её как отец (I loved that girl, but I hasten to clarify: I loved her like a father).
The other word you can use is ляпнуть, to blurt something out, usually something that you shouldn't say — like the date of someone's upcoming surprise birthday party. Он ляпнул там что-то, может быть, не совсем трезвый (He blurted something out — maybe he wasn't quite sober). Я ляпнул первое, что пришло в голову (I blabbed the first thing that came to mind).
And that's about it for misspeaking in Russian. You can't put your foot in your mouth in Russian, but you can compare saying the wrong thing to stumbling: Лучше оступиться, чем оговориться (better to trip than to have a slip of the tongue).
That doesn't mean that you can't express dismay at what you've said in Russian. You can, in lots of ways. But these words and phrases don't so much describe the verbal gaffe as express your sense of guilt and discomfort.
My favorite is сесть в лужу (literally, to sit down in a puddle). This expression is used to describe goofing up big-time and finding yourself in an uncomfortable situation of your own making. So you could say this about misspeaking: Ольга в очередной раз говорила не то и села в лужу (For the nth time Olga said the wrong thing and got herself in a real bind). But it refers to looking like a jerk for any reason: Его пригласили как квалифицированного переводчика, а он сел в лужу (Thinking that he was a qualified interpreter, they gave him a job, but he really screwed up).
Another way of saying that you got yourself into a mess is попасть впросак: То и дело он попадал впросак, писал не то, что нужно (From time to time he got himself into trouble for writing what he shouldn't have).
But this is for underlings. The folks up top don't ever seem to get in trouble for their words or actions. Donald Trump, eat your heart out.