"dead seriousness" is a correct phrase and is often used in written English.
It means to be completely serious or sincere about something. Example: We need to approach this project with dead seriousness. Our company's reputation is on the line.
That dead seriousness in Fallon is interesting to watch.
It looks funny, but its geometric formations are choreographed with dead seriousness.
Torre's face went from almost bemusement at the sign to one of dead seriousness.
This is a sumptuous record that isn't particularly relaxing to hear; its dead seriousness is hard to miss.
After turning out some funny books about the perils of life in suburbia, Linwood Barclay jumped the fence and started writing with dead seriousness on the same subject.
The vision was offered up in dead seriousness last week by Ewald Nowotny, president of the National Bank of Austria and a member of the E.C.B.'s governing council.
I knew this whole thing was no big deal, but the dead-seriousness of the guard threw me on my heels.
For reasons I don't quite understand, the dead-seriousness of Mr. Hoffman's efforts don't add heft to "Rain Man". In much the way that Raymond stays detached, the performance seems to exist outside the film but, instead of illuminating "Rain Man," it upstages the work of everyone else involved.
Macedonians approach gambling with utter seriousness.
Where former campaign chief Paul Manafort brought Republican party approval and the dead-eyed seriousness of a consultant who helped elect strongmen in Ukraine, Bannon is intended to bring back the wild spirit of revolution to a candidate who has upset the established order all year.
Harvey's work has always been tethered to the kind of deep seriousness that acts as a dead weight on any artist without both the strength of purpose and the craft to carry it along with them.
