Frequency: The word is one of the 3000 most common words in English.
1.
Something that is ~ is very large in size, quantity, or extent.
There was evidence of ~ fraud.
...~ air attacks...
The scale of the problem is ~.
= huge
ADJ emphasis
~ly
...a ~ly popular game...
ADV
2.
If you describe a medical condition as ~, you mean that it is extremely serious.
He died six weeks later of a ~ heart attack.
ADJ: ADJ n