The comparative and superlative of �fast �:

faster than, the fastest

more fast than, the most fast

Long answer: with the exception of the very few irregular adjectives (good, bad, far, many/much, and sometimes old), one-syllable adjectives use -er and -est for the comparative and superlative forms. Adjust spelling in the same way you would for -ed, (e.g., dry/drier/driest, wide/wider/widest, and mad/madder/maddest).

 

For two-syllable adjectives, use the -er and -est endings if the word ends with e, y, or ow. (Change y to I if there �s a consonant before the y.)

 

For other two-syllable adjectives or longer adjectives, use more and most.

 

For most adverbs, use more or most. For well or badly, use better/best or worse/worst.

 

I hope this explains everything.