Definitions of lightly:

• adverb:   with indifference or without dejection

  Example: "He took it lightly"

• adverb:   indulging with temperance

  Example: "We eat lightly in the morning"

• adverb:   to a slight degree

  Example: "Her speech is only lightly accented"

• adverb:   with little weight or force

  Example: "She kissed him lightly on the forehead"

• adverb:   with few burdens
• adverb:   without good reason

  Example: "One cannot say such things lightly"

• adverb:   in a small quantity or extent

  Example: "Apply paint lightly"