1. based on or subject to individual discretion or preference or sometimes impulse or caprice;

- Example: "an arbitrary decision"

- Example: "the arbitrary rule of a dictator"

- Example: "an arbitrary penalty"

- Example: "of arbitrary size and shape"

- Example: "an arbitrary choice"

- Example: "arbitrary division of the group into halves"

The Collaborative International Dictionary of English v.0.48:

Arbitrary \Ar"bi*tra*ry\, a. [L. arbitrarius, fr. arbiter: cf. F. arbitraire. See Arbiter.] 1. Depending on will or discretion; not governed by any fixed rules; as, an arbitrary decision; an arbitrary punishment. [1913 Webster] It was wholly arbitrary in them to do so. --Jer. Taylor. [1913 Webster] Rank pretends to fix the value of every one, and is the most arbitrary of all things. --Landor. [1913 Webster] 2. Exercised according to one's own will or caprice, and therefore conveying a notion of a tendency to abuse the possession of power. [1913 Webster] Arbitrary power is most easily established on the ruins of liberty abused licentiousness. --Washington. [1913 Webster] 3. Despotic; absolute in power; bound by no law; harsh and unforbearing; tyrannical; as, an arbitrary prince or government. --Dryden. [1913 Webster] Arbitrary constant, Arbitrary function (Math.), a quantity of function that is introduced into the solution of a problem, and to which any value or form may at will be given, so that the solution may be made to meet special requirements. Arbitrary quantity (Math.), one to which any value can be assigned at pleasure. [1913 Webster]WordNet (r) 3.0 (2006):

arbitrary adj 1: based on or subject to individual discretion or preference or sometimes impulse or caprice; "an arbitrary decision"; "the arbitrary rule of a dictator"; "an arbitrary penalty"; "of arbitrary size and shape"; "an arbitrary choice"; "arbitrary division of the group into halves" [ant: nonarbitrary, unarbitrary]Moby Thesaurus II by Grady Ward, 1.0:

133 Moby Thesaurus words for "arbitrary": absolute, absolutist, absolutistic, aristocratic, arrogant, autarchic, authoritarian, authoritative, autocratic, autonomous, bossy, capricious, careless, chance, chancy, cranky, crotchety, despotic, dictatorial, discretional, discretionary, dogmatic, domineering, doubtful, elective, erratic, fanciful, fantasied, fantastic, feudal, flaky, freakish, free, free will, gratuitous, grinding, harebrained, heedless, high-handed, humorsome, iffy, imperative, imperial, imperious, impetuous, inadvertent, inconsiderate, inconsistent, independent, indiscreet, irrational, kinky, kooky, lordly, maggoty, magisterial, magistral, masterful, monocratic, moody, motiveless, nonmandatory, notional, offered, oppressive, optional, oracular, overbearing, overruling, peremptory, petulant, precipitate, proffered, quirky, random, rash, reasonless, repressive, screwball, self-acting, self-active, self-determined, self-determining, severe, spontaneous, strict, subjective, summary, suppressive, temperamental, thoughtless, tyrannical, tyrannous, unasked, unbesought, unbidden, uncalculating, uncalled-for, uncertain, uncoerced, uncompelled, uncompromising, unconstrained, undisciplined, unforced, unguarded, uninfluenced, uninvited, unpredictable, unpressured, unprompted, unreasonable, unreasoning, unreflecting, unrequested, unrequired, unrestrained, unruly, unsolicited, unsought, unthinking, unthoughtful, vagarious, vagrant, varying, voluntary, volunteer, wanton, wayward, whimsical, wild, willful, zanyBouvier's Law Dictionary, Revised 6th Ed (1856):

ARBITRARY. What depends on the will of the judge, not regulated or established by law. Bacon (Aphor. 8) says, Optima lex quae minimum relinquit arbitrio judicis et (Aph. 46) optimus judex, qui mi nimum sibi 2. In all well adjusted systems of law every thing is regulated, and nothing arbitrary can be allowed; but there is a discretion which is sometimes allowed by law which leaves the judge free to act as he pleases to a certain extent. See Discretion