The Collaborative International Dictionary of English v.0.48:

Scruple \Scru"ple\, v. t.
   1. To regard with suspicion; to hesitate at; to question.
      [1913 Webster]

            Others long before them . . . scrupled more the
            books of heretics than of gentiles.   --Milton.
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   2. To excite scruples in; to cause to scruple. [R.]
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            Letters which did still scruple many of them. --E.
                                                  Symmons.
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The Collaborative International Dictionary of English v.0.48:

Scruple \Scru"ple\, n. [L. scrupulus a small sharp or pointed
   stone, the twenty-fourth part of an ounce, a scruple,
   uneasiness, doubt, dim. of scrupus a rough or sharp stone,
   anxiety, uneasiness; perh. akin to Gr. ? the chippings of
   stone, ? a razor, Skr. kshura: cf. F. scrupule.]
   1. A weight of twenty grains; the third part of a dram.
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   2. Hence, a very small quantity; a particle.
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            I will not bate thee a scruple.       --Shak.
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   3. Hesitation as to action from the difficulty of determining
      what is right or expedient; unwillingness, doubt, or
      hesitation proceeding from motives of conscience.
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            He was made miserable by the conflict between his
            tastes and his scruples.              --Macaulay.
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   To make scruple, to hesitate from conscientious motives; to
      scruple.                                    --Locke.
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The Collaborative International Dictionary of English v.0.48:

Scruple \Scru"ple\, v. i. [imp. & p. p. Scrupled; p. pr. & vb.
   n. Scrupling.]
   To be reluctant or to hesitate, as regards an action, on
   account of considerations of conscience or expedience.
   [1913 Webster]

         We are often over-precise, scrupling to say or do those
         things which lawfully we may.            --Fuller.
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         Men scruple at the lawfulness of a set form of divine
         worship.                                 --South.
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WordNet (r) 3.0 (2006):

scruple
    n 1: a unit of apothecary weight equal to 20 grains
    2: uneasiness about the fitness of an action [syn: scruple,
       qualm, misgiving]
    3: an ethical or moral principle that inhibits action
    v 1: hesitate on moral grounds; "The man scrupled to perjure
         himself"
    2: raise scruples; "He lied and did not even scruple about it"
    3: have doubts about

Moby Thesaurus II by Grady Ward, 1.0:

235 Moby Thesaurus words for "scruple":
   Pyrrhonism, ace, apprehension, atom, awake a doubt, back down,
   balance, balk, balk at, bashfulness, be diffident, be doubtful,
   be dubious, be skeptical, be uncertain, beef, better self, bit,
   bitch, blench, boggle, boggling, boycott, call in question,
   challenge, complain, complaint, compunction, conscience,
   conscientiousness, contest, cry out against, dab, debate,
   deliberate, demonstrate, demonstrate against, demonstration, demur,
   demurral, demurrer, diffidence, discomfort, dispute, distrust,
   distrustfulness, dole, dot, doubt, doubtfulness, dram, dribble,
   driblet, dubiety, dubiousness, dwarf, enter a protest, exception,
   expostulate, expostulation, falter, faltering, farthing,
   fastidiousness, fear, fight shy of, fleck, flinch, flyspeck,
   fragment, fret, gag, gobbet, grain, granule, greet with skepticism,
   grievance, grievance committee, groat, hair, half believe,
   half-belief, handful, hang back, hang off, harbor suspicions,
   have qualms, have reservations, hem and haw, hesitance, hesitancy,
   hesitate, hesitation, hold off, holler, hover, howl, hum and haw,
   indignation meeting, iota, jib, jot, kick, leeriness, little,
   little bit, lota, make bones about, march, meticulousness, minim,
   minimum, minutiae, misdoubt, misgive, misgiving, mistrust,
   mistrustfulness, mite, modesty, modicum, molecule, mote,
   nonviolent protest, nutshell, object, objection, ounce,
   overconscientiousness, overscrupulousness, pangs,
   pangs of conscience, particle, pause, pebble, picket, picketing,
   pinch, pittance, point, point of honor, ponder, press objections,
   pricking of heart, protest, protest demonstration, protestation,
   pull back, punctilio, punctiliousness, quail, qualm,
   qualm of conscience, qualmishness, qualms, query, question,
   raise a howl, raise a question, rally, recoil, reconsideration,
   reluctance, remonstrance, remonstrate, remonstration, retreat,
   scrap, scruples, scrupulosity, scrupulousness, second thought,
   second thoughts, self-doubt, shadow of doubt, shilly-shally, shred,
   shrink, shrink from, shrinking, shy, shy at, shyness, sit in,
   sit-in, skepticalness, skepticism, smell a rat, smidgen, smitch,
   speck, spoonful, spot, squawk, squeamishness, state a grievance,
   stick, stick at, stickle, stickling, stop to consider,
   straddle the fence, strain, strain at, strike, stumble, suspect,
   suspicion, suspiciousness, teach in, teach-in, thimbleful,
   think twice about, throes, throw doubt upon, tiny bit, tittle,
   total skepticism, touch of conscience, treat with reserve,
   trifling amount, trivia, twinge of conscience, uncertainty,
   uneasiness, vacillate, voice of conscience, wariness, waver, whit,
   wince, withdraw, worry, yell bloody murder, yield