엄청나요 · 엄청났어요 · 엄청난 (+noun)
enormous, tremendous, incredible
Example
어제 콘서트에 엄청난 수의 사람들이 모여서 깜짝 놀랐어요.
I was shocked that an enormous crowd gathered at the concert yesterday.
Word parts
The adverb 엄청 (super, really) is hugely common in casual speech.
Related words