Sometimes spelled with an f, as in eufemism.
Trying to make the mean things you say sound nicer (example 2) or making a mild comment you make sound even worse by adding you were just using an euphemism (example 1).
Jack: o my God, I really hate that Grace-woman! Why is she coming over instead of DROPPING DEAD?
Karen: o come on, she's not that bad.
Jack: she is! And I'm telling her, just wait.
Grace: hi guys!
Jack: I'm really sorry, Grace, but I just don't like you very much. And that is really just an euphemism. Bye bye now!
Grace: o my God! I'm outta here!
Pete: okay, well, it's not the best painting in the world...
Joan: yeah, nice euphemism, Pete. This is without a doubt the worst painting I have ever seen. Seriously, even a two-year-old would do a much better job!