How does it change a word when you add -isima, -isimo?

Question

How does it change a word when you add the ending -isima or -isimo to an adjective.

Answer 1

HI mella, last answer today: it makes the word superlative

guapa: pretty

guapísima: veeeeery pretty

Answer 2

That is a very helpful table. Thank you.

Answer 3

Have a look at this discussion of suffixes from the University of Chicago Spanish Dictionary 5th edition, pages 7 and 8, I think.