Definitions of less:

• adjective:   (nonstandard in some uses but often idiomatic with measure phrases) fewer

  Example: "Less than three weeks"

• adjective:   (usually preceded by `no') lower in esteem

  Example: "No less a person than the king himself"

• adjective:   (usually preceded by `no') lower in quality

  Example: "No less than perfect"

• adverb:   used to form the comparative of some adjectives and adverbs

  Example: "Less interesting"

• adverb:   comparative of little

  Example: "She walks less than she should"

• name:  A surname (very rare: popularity rank in the U.S.: #31634)