The phrase "a far more grave" is correct and usable in written English.
It can be used to emphasize the seriousness of a situation or issue in comparison to something else.
Example: "The consequences of ignoring climate change are a far more grave concern than we previously thought."
Alternatives: "a much more serious" or "a significantly more severe".
In his cowardice, Obama has become complicit in a sort of wounding far more grave than Turkish pride: that of the Armenians whose lore includes watching their forebears forcibly deported and summarily executed, their bodies deposed in mass graves or floated down rivers into oblivion.
Still, the death defined the trial, turning what might have been a peeping Tom case or, as the resident assistant said, "a roommate issue" into something far more grave.
The errors in judgment at the C.I.A. and the F.B.I had far more grave consequences than Enron's collapse, and some of the errors could have been avoided.
(It also turns out that one of the women has gone to the game for reasons far more grave than fandom.) Part of the films risky, transgressive energy arises from the circumstances of its making.
While parallels have been made between the Mineo and Louima cases, Mr. Louima's injuries were far more grave and required him to undergo emergency surgery and to be hospitalized for two months.
The crisis, American officials say, is far more grave than the political tensions between the Shiite-dominated government of Prime Minister Nuri Kamal al-Maliki and the country's Sunni Arab minority set off by an arrest warrant on terrorism charges issued in December for Tariq al-Hashimi, the Sunni vice president.
The film sees all three of its lead characters hover on the brink of adolescence, "and while they look braver and more capable than before, the dangers they face seem far more grave and their own vulnerability more intense".
There are far more graves than living souls here.
James Salter is a far more unusual case.
A far more fundamental objection was stylistic.
