What is the meaning of scruples?

noun

• A unit of apothecary weight equal to 20 grains.
  • synonyms: scruple
• Uneasiness about the fitness of an action.
  • synonyms: scruple, qualm, misgiving
• An ethical or moral principle that inhibits action.
  • synonyms: scruple
• Motivation deriving logically from ethical or moral principles that govern a person's thoughts and actions.
  • synonyms: conscience, moral sense, sense of right and wrong

verb

• Hesitate on moral grounds.
  • usage: "The man scrupled to perjure himself"
  • synonyms: scruple
• Raise scruples.
  • usage: "He lied and did not even scruple about it"
  • synonyms: scruple
• Have doubts about.
  • synonyms: scruple