The phrase "terribly likely" is correct and usable in written English.
You can use it to indicate that something is very likely to happen or be true. For example, "Given the amount of snow we've had this winter, it's terribly likely that we'll see a white Christmas this year."
Such an outcome does not look terribly likely.
This week's attack on Serbia may be the start of an admirable new trend to restrain thugs and despots, though that does not look terribly likely.
It does not seem terribly likely that Florida voters are yearning for a man who made his maxi-fortune betting that real estate prices would drop.
"If people are never asked, or are not asked in a sophisticated way, they're not terribly likely to give," he said.
Neither scenario seems terribly likely at the moment, but if this is the balance of power we're stuck with for five or ten years to come, then those are the only paths to actual policy achievements across that span.
If you mean someone who agrees that logically there could be a god, but who doesn't think that the logical possibility is terribly likely, or at least not something that should keep us awake at night, then I guess a lot of us are atheists.
Sadly, the state doesn't seem to be terribly good at picking likely staff.
They don't share much about how they come up with that number, but it's likely not terribly scientific and meant primarily as a motivation device to get people moving more frequently.
Terms of the transaction remain undisclosed, but it's likely nothing terribly material for NASDAQ-listed Autodesk, which said the transaction is expected to have zero impact on previously issued guidance.
She sat in front of police and recounted her story for them, likely in terribly vivid detail.
You will most likely feel terribly uncomfortable while you wait in the terminal or during the flight; and in some cases, make the passengers in close proximity feel that way to.
