The Collaborative International Dictionary of English v.0.48:

disregard \dis`re*gard"\, v. t. [imp. & p. p. disregarded; p.
   pr. & vb. n. disregarding.]
   Not to regard; to pay no heed to; to omit to take notice of;
   to neglect to observe; to slight as unworthy of regard or
   notice; as, to disregard the admonitions of conscience.
   [1913 Webster]

         Studious of good, man disregarded fame.  --Blackmore.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Disregard \Dis`re*gard"\, n.
   The act of disregarding, or the state of being disregarded;
   intentional neglect; omission of notice; want of attention;
   slight.
   [1913 Webster]

         The disregard of experience.             --Whewell.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disregard
    n 1: lack of attention and due care [syn: disregard,
         neglect]
    2: willful lack of care and attention [syn: disregard,
       neglect]
    v 1: refuse to acknowledge; "She cut him dead at the meeting"
         [syn: ignore, disregard, snub, cut]
    2: bar from attention or consideration; "She dismissed his
       advances" [syn: dismiss, disregard, brush aside, brush
       off, discount, push aside, ignore]
    3: give little or no attention to; "Disregard the errors" [syn:
       neglect, ignore, disregard]

Moby Thesaurus II by Grady Ward, 1.0:

353 Moby Thesaurus words for "disregard":
   abide with, abjuration, abjure, abjurement, absentmindedness,
   accept, accidia, acedia, admit, admit exceptions, allow, allow for,
   apathy, arrogance, ataraxia, ataraxy, audacity, be big,
   be blind to, be caught napping, be caught out, be content with,
   be easy with, be inattentive, be neglectful, be negligent,
   be unwary, bear with, benevolence, blink at, bold front, boldness,
   brash bearing, brashness, brassiness, bravado, brazenness,
   break the law, brook, brush aside, brush off, bumptiousness,
   care naught for, carelessness, casualness, cheekiness, chuck,
   chuck out, chucking, chucking out, cockiness, concede, condonation,
   condone, connive at, consider, consider the circumstances,
   consider the source, contemn, contempt, contemptuousness,
   contradict, contradiction, culpa, culpable negligence, cut,
   cut dead, cut direct, daring, daringness, declination, decline,
   declining, default, defial, defiance, defy, defying, delinquency,
   denial, deny, dereliction, deride, derision, despisal, despise,
   despising, despite, detachment, digest, disapproval, disapprove,
   discard, disclaim, disclamation, disconformity, discount,
   discounting, disdain, disesteem, disinterest, dismiss, dismissal,
   disobey, disown, disownment, disparage, dispassion,
   disregardfulness, disrespect, distraction, down, easygoingness,
   eat, endure, except, exception, exclude, exclusion, fail, failure,
   flightiness, flippancy, flout, forbearance, forget, forgetting,
   forgiveness, forgivingness, forswear, frivolousness, giddiness,
   give no heed, give the go-by, gloss over, go counter to, grant,
   hear nothing, heedlessness, hold in derision, humiliation, ignore,
   ignoring, impertinence, impudence, inadvertence, inadvertency,
   inattention, inattentiveness, inconsideration, incuriosity,
   indifference, indiscrimination, indulgence, inexcitability,
   inobservance, insolence, insouciance, judge not, kindness, laches,
   lack of affect, lackadaisicalness, laissez-faire, lapse, lassitude,
   laugh at, laugh to scorn, laxity, laxness, lean over backwards,
   leave unavenged, let go, let go by, let it go, let pass, let ride,
   let slide, let slip, lethargy, levity, lift temporarily,
   lightmindedness, listen to reason, listlessness, live with,
   long-suffering, longanimity, look right through, looseness,
   lose sight of, lose track of, magnanimity, make allowance for,
   make allowances for, make light of, make little of, mindlessness,
   minimize, miss, neglect, neglectfulness, neglecting, negligence,
   nod, nonacceptance, nonadherence, nonapproval, nonchalance,
   noncompliance, nonconformance, nonconformity, nonconsideration,
   nonfeasance, nonfulfillment, noninterference, nonobservance,
   nonperformance, nonrestriction, not attend, not care for,
   not conform, not get involved, not heed, not keep, not listen,
   not mind, not notice, not observe, not think, not write off,
   obliviousness, omission, omit, omitting, overlook, overlooking,
   overpass, oversight, pass by, pass over, pass up, passing by,
   patience, pay no attention, pay no mind, permissiveness, pertness,
   pocket, pocket the affront, pococurantism, pooh-pooh,
   poor stewardship, pretermit, procrastination, provide for,
   push aside, putting away, putting out, rebuff, recant, recantation,
   recklessness, refusal, refuse, refuse to acknowledge,
   refuse to consider, refuse to cooperate, refuse to recognize,
   regard with indulgence, regardlessness, reject, rejection, relax,
   relax the condition, remissness, renounce, renouncement, repel,
   repudiate, repudiation, repulse, sauciness, scoff at, scorn, scout,
   scouting, see both sides, see nothing, set aside, set at defiance,
   set at naught, set naught by, shallowness, shove away, slackness,
   sleep, slight, slight over, slighting, sloth, sneer, sneeze at,
   sniff, snort, snub, spurn, spurning, stomach, superficiality,
   suspend judgment, swallow, swallow an insult, take,
   take account of, take for granted, take into account,
   take into consideration, the cold shoulder, the go-by,
   think little of, thoughtlessness, throw away, throw out,
   throwing out, tolerance, tolerate, transgress,
   turn aside provocation, turn away, turn out, turning out,
   unalertness, unanxiousness, unawareness, unconcern,
   unconsciousness, underestimate, underrate, undervalue,
   unheedfulness, unintentiveness, unmindfulness, unobservance,
   unrevengefulness, unrigorousness, unsolicitousness, unwariness,
   unwatchfulness, view with indulgence, violate, waive, wink at