Definitions of scruple:

• noun:   an ethical or moral principle that inhibits action
• noun:   uneasiness about the fitness of an action
• noun:   a unit of apothecary weight equal to 20 grains
• verb:   hesitate on moral grounds

  Example: "The man scrupled to perjure himself"

• verb:   have doubts about
• verb:   raise scruples

  Example: "He lied and did not even scruple about it"