- I have less money than you.
- He was less hurt than frightened.
- Tom is less clever than his brother.
Fewer is the comparative of few. It is used before plural nouns.
- Fewer people live to be hundred.
In an informal style, less is quite common before plural nouns. Some people consider this incorrect.
- I have got less problems than I used to have. (Less formal than I have got fewer problems than I used to have.)
Before determiners (articles, demonstratives and possessives) and pronouns we use less of and fewer of.
- I would like to spend less of my time travelling. (NOT — less my time traveling.)
- I want less of this and more of that. (NOT I want less this —)
Before nouns without determiners, of is not used.
- If you want to lose weight, eat less food. (NOT — less of food.)
- Fewer people live to be hundred. (NOT Fewer of people —)
Lesser means ‘not so much’. It is used in a few expressions.
a lesser-known writer
the lesser of two evils.
The least means the smallest or lowest quantity or degree. It is the superlative of little. It is used before uncountable nouns.
- He went up the steps without showing the least anxiety.
- She had not the least idea of what was going on.
Before plural abstract nouns we can use the least of.
- ‘I think she is really upset with you.’ ‘That is the least of my worries.’
The fewest is the superlative of few. It is used before plural nouns.
Less and Fewer
Less is the comparative of little. It is used before uncountable nouns. Fewer is the comparative of few. It is used before plural nouns.
- New cars tend to cause less air pollution.
- He earns less money than his wife.
- I have got fewer problems than I used to have.
Note that in an informal style less is quite common before plural nouns.