Astonishing

adj.joyful, hopefulwarm

What it means

So unexpected and impressive that it causes great surprise.

Reach for it when praising an outcome whose scale genuinely exceeds expectation

The tiny telescope revealed an astonishing view of Saturn.

playful
staggering
the magnitude overwhelms expectation
not when Staggering often describes costs, losses, or other unwelcome extremes.
everyday
amazing
friendly surprise and admiration should sound natural
not when Amazing is heavily overused and may flatten a precisely measured achievement.
everyday
surprising
unexpectedness is the only claim supported
not when Surprising can describe bad or trivial news without admiration.
warm
astounding
the surprise is forceful enough to stop ordinary response
not when Astounding raises the intensity and may overstate a modest gain.
warm
breathtaking
beauty or scale produces an immediate emotional reaction
not when Breathtaking is promotional when no physical or visual impact exists.
professional
remarkable
the result deserves attention for a specific reason
not when Remarkable is measured and may not convey genuine shock.
formal
extraordinary
the achievement lies far outside ordinary quality
not when Extraordinary is a comparative judgment and need not describe surprise.

astonishing result
The second trial produced an astonishing result with half the material.
truly astonishing
The clarity of the restored recording is truly astonishing.
astonishing achievement
Crossing the ice safely was an astonishing achievement.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.