Some adjectives form their comparatives and superlatives irregularly.

 

Irregular comparatives and superlatives
The following table shows a small list of adjectives that have irregular comparatives and superlatives, which do not make use of –er, –est, more or most
 
  
Absolute Comparative Superlative
good better (than) (the) best
bad worse (than) (the) worst
little (amount) less (than) (the) least
little (size) smaller (than) (the) smallest
much more (than) (the) most
many more (than) (the) most
some more (than) (the) most
far (distance) farther (than) (the) farthest
far (advanced stage) further (than) (the) furthest