The Collaborative International Dictionary of English v.0.48:

Resistance \Re*sist"ance\ (-ans), n. [F. r['e]sistance, LL.
   resistentia, fr. resistens, -entis, p. pr. See Resist.]
   1. The act of resisting; opposition, passive or active.
      [1913 Webster]

            When King Demetrius saw that . . . no resistance was
            made against him, he sent away all his forces. --1.
                                                  Macc. xi. 38.
      [1913 Webster]

   2. (Physics) The quality of not yielding to force or external
      pressure; that power of a body which acts in opposition to
      the impulse or pressure of another, or which prevents the
      effect of another power; as, the resistance of the air to
      a body passing through it; the resistance of a target to
      projectiles.
      [1913 Webster]

   3. A means or method of resisting; that which resists.
      [1913 Webster]

            Unfold to us some warlike resistance. --Shak.
      [1913 Webster]

   4. (Elec.) A certain hindrance or opposition to the passage
      of an electrical current or discharge offered by
      conducting bodies. It bears an inverse relation to the
      conductivity, -- good conductors having a small
      resistance, while poor conductors or insulators have a
      very high resistance. The unit of resistance is the ohm.
      [1913 Webster]

   Resistance box (Elec.), a rheostat consisting of a box or
      case containing a number of resistance coils of standard
      values so arranged that they can be combined in various
      ways to afford more or less resistance.

   Resistance coil (Elec.), a coil of wire introduced into an
      electric circuit to increase the resistance.

   Solid of least resistance (Mech.), a solid of such a form
      as to experience, in moving in a fluid, less resistance
      than any other solid having the same base, height, and
      volume.
      [1913 Webster]

WordNet (r) 3.0 (2006):

resistance
    n 1: the action of opposing something that you disapprove or
         disagree with; "he encountered a general feeling of
         resistance from many citizens"; "despite opposition from
         the newspapers he went ahead" [syn: resistance,
         opposition]
    2: any mechanical force that tends to retard or oppose motion
    3: a material's opposition to the flow of electric current;
       measured in ohms [syn: electric resistance, electrical
       resistance, impedance, resistance, resistivity, ohmic
       resistance]
    4: the military action of resisting the enemy's advance; "the
       enemy offered little resistance"
    5: (medicine) the condition in which an organism can resist
       disease [syn: immunity, resistance]
    6: the capacity of an organism to defend itself against harmful
       environmental agents; "these trees are widely planted because
       of their resistance to salt and smog"
    7: a secret group organized to overthrow a government or
       occupation force [syn: underground, resistance]
    8: the degree of unresponsiveness of a disease-causing
       microorganism to antibiotics or other drugs (as in
       penicillin-resistant bacteria)
    9: (psychiatry) an unwillingness to bring repressed feelings
       into conscious awareness
    10: an electrical device that resists the flow of electrical
        current [syn: resistor, resistance]
    11: group action in opposition to those in power

Moby Thesaurus II by Grady Ward, 1.0:

298 Moby Thesaurus words for "resistance":
   Charley, VC, Vietcong, acquired immunity, active immunity,
   alienation, antagonism, antibody, antigen, antipathy, arrest,
   arrestation, arrestment, artificial immunity, autism,
   autistic thinking, averseness, aversion, avoidance mechanism,
   avoidance reaction, backlash, backwardness, base resistance,
   blame-shifting, block, blockage, blocking, bucking, bushfighter,
   bushwhacker, callosity, callousness, capacitive reactance, casual,
   censorship, challenge, check, clashing, clogging, closing up,
   closure, coefficient of friction, cohesiveness, collision,
   compensation, conflict, confutation, congenital immunity,
   constriction, contention, contradiction, contraposition,
   contrariety, contravention, contraversion, contumaciousness,
   contumacy, counteraction, counterposition, counterworking, cramp,
   crankiness, crosscurrent, crossing, crotchetiness, cursoriness,
   decompensation, defence, defense, defense in depth,
   defense mechanism, defenses, defiance, delay, denial, density,
   dereism, dereistic thinking, detainment, detention,
   deterrent capacity, disagreement, disinclination, disobedience,
   displacement, disrelish, dissent, dissociation, distaste, drag,
   durability, durity, ego defenses, electric resistance,
   emitter resistance, emotional insulation, escape,
   escape into fantasy, escape mechanism, escapism, familial immunity,
   fantasizing, fantasy, fixation, flight, flintiness, fluid friction,
   foot-dragging, force of friction, force of viscosity,
   forward transfer resistance, fractiousness, friction,
   friction head, friction loss, frictional resistance,
   grudging consent, grudgingness, guard, guerillas, guerrilla,
   hampering, hardiness, hardness, hardness of heart, head wind,
   hindering, hindrance, holdback, holdup, immunity, immunization,
   impedance, impediment, impenetrability, impugnation, impugnment,
   incorrigibility, indisposedness, indisposition, indocility,
   indomitability, inductive reactance, induration, infrangibility,
   inherent immunity, inherited immunity, inhibition,
   input resistance, insuppressibility, interference,
   internal friction, interruption, intractability, intractableness,
   intransigence, irregular, irrepressibility, isolation, kick,
   lack of enthusiasm, lack of zeal, lastingness, leatherlikeness,
   let, magnetic reluctance, maquis, maquisard, mutinousness,
   natural immunity, negation, negative taxis, negativism, nolition,
   nonconformity, nonspecific immunity, nonsusceptibility to disease,
   nuisance value, obduracy, obstinacy, obstreperousness, obstruction,
   obstructionism, occlusion, ohm, ohmage, opposing, opposition,
   opposure, oppugnance, oppugnancy, oppugnation, opsonic immunity,
   output resistance, overcompensation, partisan, passive immunity,
   perfunctoriness, perverseness, phagocytic immunity, projection,
   protection, psychological block, psychological defenses,
   psychotaxis, racial immunity, rationalization, reactance, reaction,
   rebelliousness, rebutment, rebuttal, recalcitrance, recalcitrancy,
   recoil, refractoriness, refusal, rejection, reluctance,
   reluctivity, renitence, renitency, repercussion, repression,
   repugnance, resistance fighter, restiveness, restraint,
   restriction, retardation, retardment, revolt, rolling friction,
   ropiness, self-defense, self-preservation, self-protection,
   setback, shrewishness, skin effect, skin friction,
   sliding friction, slip friction, slowness,
   sociological adjustive reactions, solidity, specific immunity,
   specific reluctance, squeeze, stamina, standing against,
   starting friction, static friction, steeliness, stiffness,
   stoniness, stranglehold, strength, stricture, stringiness,
   stubbornness, sublimation, substitution, sulk, sulkiness, sulks,
   sullenness, suppression, surface resistance, swimming upstream,
   tenacity, the defensive, toughness, toxin-antitoxin immunity,
   traversal, unbreakability, unbreakableness, uncontrollability,
   undercurrent, underground, underground fighter, unenthusiasm,
   ungovernability, unmalleability, unmanageability, unmoldableness,
   unruliness, unsubmissiveness, untamableness, unwillingness,
   viscidity, vitality, volume resistance, ward, wildness,
   wish-fulfillment fantasy, wishful thinking, withdrawal



Bouvier's Law Dictionary, Revised 6th Ed (1856):

RESISTANCE. The opposition of force to force.
     2. Resistance is either lawful or unlawful. 1. It is lawful to resist
one who is in the act of committing a felony or other crime, or who
maliciously endeavors to commit such felony or crime. See self defence. And
a man may oppose force to force against one who endeavors to make an arrest,
or to enter his house without lawful authority for the purpose; or, if in
certain cases he abuse such authority, and do more than he was authorized to
do; or if it turn out in the result he has no right to enter, then the party
about to be imprisoned, or whose house is about to be illegally entered, may
resist the illegal imprisonment or entry by self-defence, not using any
dangerous weapons, and may escape, be rescued, or even break prison, and
others may assist him in so doing. 5 Taunt. 765; 1 B. & Adol, 166; 1 East,
P. C. 295; 5 East, 304; 1 Chit. Pr. 634. See Regular and Irregular Process.
     3.-2. Resistance is unlawful when the persons having a lawful
authority to arrest, apprehend, or imprison, or otherwise to advance or
execute the public justice of the country, either civil or criminal, and
using the proper means for that purpose, are resisted in so doing; and if
the party guilty of such resistance, or others assisting him, be killed in
the struggle, such homicide is justifiable; while on the other hand, if the
officer be killed, it will, at common law, be murder in those who resist.
Fost. 270; 1 Hale, 457; 1 East, P. C. 305.