Extreme adjectives are words that give extra emphasis to the subject they describe: For example, "funny" is a normal adjective expressing that something makes us laugh, but "hilarious" is an extreme adjective which shows that something makes us laugh a lot. In other words, "hilarious" means "very funny".
In most cases, it is not necessary to use "very" with extreme adjectives e.g. "This movie's very hilarious", sounds a little strange because "hilarious" is a strong enough word that doesn't require "very" to add extra strength. Here are more examples along with their meanings.
Boiling - very hot
Freezing - very cold
Huge - Very big
Tiny - very small
Filthy - very dirty
Spotless - very clean
Furious - very angry
Exhausted - very tired
Packed - very crowded
Ancient - very old
Now complete these sentences with the best extreme adjective from the examples above.