earth-shaking
They do not view this as an earth-shattering breakthrough.
He didn't think his invention was all that earth-shattering.
The new model does not feature any earth-shattering changes to its functionality.
She couldn't have foreseen that her actions would have such earth-shattering results.

SMART Vocabulary: related words and phrases

Very important or urgent
all-important
at all costsidiom
be a matter of life and/or deathidiom
cardinally
chief
imperative
last but not leastidiom
leading
life-altering
life-and-death
life-changing
overriding
primary
prime
principally
prior
prized
seminal
tectonic
weighty

You can also find related words, phrases, and synonyms in the topics:

Surprising and shocking