"most terribly" is a correct and usable phrase in written English.
It is used to add emphasis to how terrible something is. Example: "The news of her passing affected me most terribly."
Clarkson: I'm most terribly sorry.
However, what most terribly damaged life and security was sickness.
"I have the most terribly responsible job any man ever had".
It was "the most terribly anxious night I ever passed," confessed Higginson in his journal.
It is a warning about the dangers of employing management consultants.Mrs Tittlemouse is "a most terribly tidy particular little mouse", forever cleaning her house and shooing away intruders.
Most terribly, I thought of Beethoven as the calm confectioner of the "Moonlight" Sonata; I heard the beauty, but not much more.
"Maybe the murder scene was not random, but rather a deliberately selected scene for a bloodbath on the Swedes at the most people terribly symbolic place of all, Ikea?" wrote right-wing Swedish blogger Percy Rosengren.
Hospitals are still on standby, waiting and hoping to be flooded with injured victims, but most are still terribly quiet.
Because the upside of people's unwillingness to be corralled by politicians is that most are not terribly committed to any party.
"Most parents are terribly frightened and loath to put a child on medication, and it's the kind of thing they would do when everything else has been tried," said Dr. Jensen, who added that medication is usually combined with behavior therapy or parenting advice.
Its (now former) leader Pauline Marois mooted a third referendum on "sovereignty" for Quebec, but doing so proved a tactical mistake: with most Quebeckers not terribly keen to reopen that particular issue the Parti Québécois won just 25% of the vote and 30 seats, its worst showing in more than 40 years.
