Less is the comparative form of the word little. It can be used in a variety of situations.

As a determiner

As a determiner, less is used before a noun.

• My doctor has advised me to eat less fat.
• Schools put less emphasis on physical activity.

As an adverb

As an adverb, less is used before an adjective or another adverb.

• That project was less profitable.

Less is used to refer to an amount that is smaller than another amount.

• You should eat less meat and more vegetables.
• This model uses less fuel than the earlier models.
• If you really want to get out of this debt trap, you should learn to spend less money.

Before a pronoun or a noun with a determiner, we use less of.

• I would like to spend less of my time working.
• He spends less of his time with her.

A little less / a bit less

These expressions are used for emphasizing a certain idea.

• I was a little less disappointed with her performance.
• I wish you would do a bit less talking.

Much less / a lot less

• Profits were a lot less than we were expecting.
• The job was a lot less difficult than I expected.

Less and fewer

These words are often confused.

Less is the comparative form of little. It is mainly used before uncountable nouns. Fewer is the comparative form of few. It is used with plural nouns.

• A good writer should be able to express more ideas using fewer words.