There are a few irregular adjectives and adverbs
•good → better / the best
•well → better / the best
•bad → worse / the worst
•badly → worse / the worst
•much / many → more / the most
•little → less / the least
•far → farther / the farthest or further / the furthest
•old →
•elder / the eldest (about family)
•older / the oldest (about things or people)
•little → less / the least (with uncountable nouns)
👉 I have less money than yesterday (money is uncountable)
👉 She works less than Tomas
•few → fewer / the fewest (with countable nouns)
👉 I have fewer euros than yesterday (euros is countable)
👉 There are fewer people in class today