scruple

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An uneasy feeling arising from conscience or principle that tends to hinder action.
• noun A unit of apothecary weight equal to about 1.3 grams, or 20 grains.
• noun A minute part or amount.
• intransitive verb To hesitate as a result of conscience or principle.

from The Century Dictionary.

• noun Perplexity, trouble, or uneasiness of conscience; hesitation or reluctance in acting, arising from inability to satisfy conscience, or from the difficulty of determining what is right or expedient; doubt; backwardness in deciding or acting.
• To have scruples; be reluctant as regards action or decision; hesitate about doing a thing; doubt; especially, to have conscientious doubts.
• Synonyms Scruple, Hesitate, Waver. We waver through irresolution, and hesitate through fear, if only the fear of making a mistake. Scruple has tended more and more to limitation to a reluctance produced by doubt as to the right or the propriety of the thing proposed.
• To have scruples about; doubt; hesitate with regard to; question; especially, to have conscientious doubts concerning: chiefly with an infinitive as object (now the only common use).
• noun A unit of weight, the third part of a dram, being ounce in apothecaries' weight, where alone it is now used by English-speaking people: this is 20 grains (= 1.296 grams).
• noun A small fraction.
• noun Eighteen seconds of time.
• noun One twelfth of an inch; a line.
• noun One tenth of a geometrical inch.
• noun A digit; the twelfth part of the sun's or moon's diameter.
• noun Hence, figuratively
• noun A small part; a little of anything, chiefly in negative phrases: sometimes confused with scruple.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To be reluctant or to hesitate, as regards an action, on account of considerations of conscience or expedience.
• noun A weight of twenty grains; the third part of a dram.
• noun Hence, a very small quantity; a particle.
• noun Hesitation as to action from the difficulty of determining what is right or expedient; unwillingness, doubt, or hesitation proceeding from motives of conscience.
• noun to hesitate from conscientious motives; to scruple.
• transitive verb To regard with suspicion; to hesitate at; to question.
• transitive verb rare To excite scruples in; to cause to scruple.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete A weight of twenty grains; the third part of a dram.
• noun obsolete Hence, a very small quantity; a particle.
• noun Hesitation as to action from the difficulty of determining what is right or expedient; unwillingness, doubt, or hesitation proceeding from motives of conscience; to consider if something is ethical.
• noun obsolete A doubt or uncertainty concerning a matter of fact; intellectual perplexity.
• noun A measurement of time. Hebrew culture broke the hour into 1080 scruples.
• verb intransitive To be reluctant or to hesitate, as regards an action, on account of considerations of conscience or expedience.
• verb To regard with suspicion; to hesitate at; to question.
• verb obsolete To doubt; to question; to hesitate to believe; to question the truth of (a fact, etc.).
• verb To excite scruples in; to cause to scruple.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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