There's been a lot of discussion of what Joe Biden apparently said to Barack Obama at the HCR signing ceremony:
When he turns to the president, some combination of careful listening and lip-reading suggests that Biden said "((this is)) a big fucking deal".
I'm not interested in whether and how the FCC should get involved in the use of a taboo word on the air — or whether it matters that you need a good imagination to be sure that you heard it – but rather in something about the part of the remark that remains if we leave the taboo word out.
As the OED tells us, "a big deal" (with or without the taboo intensifier) is an American expression for "Something considered important; a cause for excitement or concern." But the phrase is also "Used as an ironical exclamation to express one's contempt for something regarded as impressive or important by another person."
However, the contemptuous sense seems to be associated specifically with the exclamatory fragment "big deal", where the determiner is omitted. That version can't be used predicatively: "This is big deal" might be the boast of a Russian who never mastered the English determiner system, but it's not something that a native speaker would say "to express contempt for something regarded as impressive by another person".
Idiomatic contempt aside, the anarthrous exclamatory fragment "big deal" is syntactically regular, in that there are lots of other adjective+noun combinations used in a similar way. Some of them are also normally ironic, like "smooth move", but most may be sincere: "good man", "nice try", "cute shoes", "great idea", …
There are always corresponding regular nouns phrases, like "a great idea" or "those cute shoes". But the idiomatic irony associated with "big deal" seems to be limited to the isolated exclamatory form — and in the same way, the isolated exclamatory form in that case seems to be only the ironic idiom.
Thus vice-president Biden said "((that's)) a big fucking deal", and, I imagine, meant it sincerely. But if he'd said just "big fucking deal" it would have been a deflating attempt to subvert the moment.
The anarthrous exclamatory fragments are constrained in ways that are not entirely clear to me. For example, if you taste some soup with too much salt in it, you can certainly exclaim "wow, this soup is really salty!", but the anarthrous exclamative "salty soup!" doesn't seem to me to work.
Perhaps the exclamations are supposed to be at least nominally positive. Thus "tasty soup!" works, and "spicy soup!" seem appropriate if you like it that way, but not if you don't. But "tough luck!", though expressing support for the victim, involves a negative judgment about the event. I bet that someone has studied this.
The idiomatic irony of "big deal!" means that the valence constraint is inverted — you can safely say "big deal!" only to express contempt, not to express admiration. Luckily for president Obama, vice-president Biden seems to have started his remark with "this is a…". Otherwise, the commentariat would be buzzing a different buzz.