impossibly
adv.in a way that is very difficult or impossible to do. You use this when something seems so hard that you think it cannot be done at all.
adv.in a manner that is extremely difficult or impossible to achieve. Often used to emphasize the degree of difficulty or the impossibility of a situation.
“The task is impossibly difficult for a beginner.”
“The mountain peak was impossibly high, making the climb seem like a dream rather than a reality.”
“The architect's vision was impossibly ambitious for the budget, requiring materials and labor that the city council could not afford to provide.”
“Lowanro City’s skyline is dominated by an oppressive clock tower, silhouetted against a moody red sky and an impossibly large, ominous moon.”
“This was the point where the project stopped feeling fun and started feeling impossibly hard.”
From impossible + -ly.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.