The word "less" is a comparative form of the adjective "little." It is used to denote a smaller amount or degree of something in comparison to another quantity or level. For example, if you say "less sugar," it means a smaller amount of sugar than some reference point.
The word "less" comes from the Old English word "læs" which is related to the Proto-West Germanic term lessa. Its roots can be traced back to the Proto-Germanic lisa, which also conveys the concept of a smaller amount or degree.