The Collaborative International Dictionary of English v.0.48:

Slur \Slur\, n.
   1. A mark or stain; hence, a slight reproach or disgrace; a
      stigma; a reproachful intimation; an innuendo. "Gaining to
      his name a lasting slur." --South.
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   2. A trick played upon a person; an imposition. [R.]
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   3. (Mus.) A mark, thus [[upslur] or [downslur]], connecting
      notes that are to be sung to the same syllable, or made in
      one continued breath of a wind instrument, or with one
      stroke of a bow; a tie; a sign of legato.
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   4. In knitting machines, a contrivance for depressing the
      sinkers successively by passing over them.
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The Collaborative International Dictionary of English v.0.48:

Slur \Slur\ (sl[^u]r), v. t. [imp. & p. p. Slurred (sl[^u]rd);
   p. pr. & vb. n. Slurring (sl[^u]r"r[i^]ng).] [Cf. OE. sloor
   mud, clay, Icel. sl[=o]ra, slo[eth]ra, to trail or drag one's
   self along, D. sleuren, sloren, to train, to drag, to do
   negligently and slovenly, D. sloor, sloerie, a sluttish
   girl.]
   1. To soil; to sully; to contaminate; to disgrace.
      --Cudworth.
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   2. To disparage; to traduce. --Tennyson.
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   3. To cover over; to disguise; to conceal; to pass over
      lightly or with little notice.
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            With periods, points, and tropes, he slurs his
            crimes.                               --Dryden.
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   4. To cheat, as by sliding a die; to trick. [R.]
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            To slur men of what they fought for.  --Hudibras.
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   5. To pronounce indistinctly; as, to slur syllables; to slur
      one's words.
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   6. (Mus.) To sing or perform in a smooth, gliding style; to
      connect smoothly in performing, as several notes or tones.
      --Busby.
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   7. (Print.) To blur or double, as an impression from type; to
      mackle.
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WordNet (r) 3.0 (2006):

slur
    n 1: (music) a curved line spanning notes that are to be played
         legato
    2: a disparaging remark; "in the 19th century any reference to
       female sexuality was considered a vile aspersion"; "it is
       difficult for a woman to understand a man's sensitivity to
       any slur on his virility" [syn: aspersion, slur]
    3: a blemish made by dirt; "he had a smudge on his cheek" [syn:
       smudge, spot, blot, daub, smear, smirch, slur]
    v 1: play smoothly or legato; "the pianist slurred the most
         beautiful passage in the sonata"
    2: speak disparagingly of; e.g., make a racial slur; "your
       comments are slurring your co-workers"
    3: utter indistinctly
    4: become vague or indistinct; "The distinction between the two
       theories blurred" [syn: blur, dim, slur] [ant:
       focalise, focalize, focus]

Moby Thesaurus II by Grady Ward, 1.0:

182 Moby Thesaurus words for "slur":
   accent, accent mark, affront, asperse, aspersion, attaint,
   bad-mouth, badge of infamy, bar, bar sinister, baton, bedaub,
   befoul, bend sinister, besmear, besmirch, besmoke, bespatter,
   bestain, black eye, black mark, blacken, blink, blot, blow upon,
   blur, brand, broad arrow, calumniate, calumny, cancel, cantando,
   carefully ignore, cast aspersions on, cast reflections on, censure,
   champain, character, cold-shoulder, custos, cut a corner,
   cut corners, darken, daub, defame, defile, demilegato, denigrate,
   dip into, direct, dirty, disapprove, discolor, discredit,
   disparage, disparagement, disregard, dodge, dot, examine cursorily,
   execution, expose, expose to infamy, expression, expression mark,
   fermata, fingering, fudge, garble, gibbet, give the once-over,
   glance at, glissando, gloss over, hang in effigy, hold, ignore,
   imputation, innuendo, insinuation, insult, intonation,
   key signature, lead, legato, libel, ligature, lisp, malign, mark,
   mark of Cain, measure, metronomic mark, mezzo staccato, mumble,
   music-making, notation, obloquy, odium, onus, page through,
   parlando, pass over, pass over lightly, pause, performance,
   personal remark, personality, pianism, pillory, pillorying,
   pizzicato, point champain, presa, put-down, reflection, rendering,
   rendition, repercussion, reprimand, reproach, rubato, scamp, scan,
   scorch, sear, segno, sign, signature, singe, skid, skim, skim over,
   skim the surface, skimp, skip over, slam, slander, slidder, slight,
   slip, slip through, slubber, slubber over, slur over,
   sly suggestion, smear, smirch, smoke, smudge, smutch, soil,
   spiccato, spot, staccato, stain, stigma, stigmatism,
   stigmatization, stigmatize, stricture, stutter, suggestion, sully,
   swell, symbol, taint, tarnish, tear down, tempo mark,
   thumb through, tie, time signature, touch, touch upon,
   touch upon lightly, traduce, uncomplimentary remark, vilify,
   vinculum, whispering campaign, zip through