The Collaborative International Dictionary of English v.0.48:

Magnify \Mag"ni*fy\, v. t. [imp. & p. p. Magnified; p. pr. &
   vb. n. Magnifying.] [OE. magnifien, F. magnifier, L.
   magnificare. See Magnific.]
   1. To make great, or greater; to increase the dimensions of;
      to amplify; to enlarge, either in fact or in appearance;
      as, the microscope magnifies the object by a thousand
      diameters.
      [1913 Webster]

            The least error in a small quantity . . . will in a
            great one . . . be proportionately magnified.
                                                  --Grew.
      [1913 Webster]

   2. To increase the importance of; to augment the esteem or
      respect in which one is held.
      [1913 Webster]

            On that day the Lord magnified Joshua in the sight
            of all Israel.                        --Joshua iv.
                                                  14.
      [1913 Webster]

   3. To praise highly; to laud; to extol. [Archaic]
      [1913 Webster]

            O, magnify the Lord with me, and let us exalt his
            name together.                        --Ps. xxxiv.
                                                  3.
      [1913 Webster]

   4. To exaggerate; as, to magnify a loss or a difficulty.
      [1913 Webster]

   To magnify one's self (Script.), to exhibit pride and
      haughtiness; to boast.

   To magnify one's self against (Script.), to oppose with
      pride.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Magnify \Mag"ni*fy\, v. i.
   1. To have the power of causing objects to appear larger than
      they really are; to increase the apparent dimensions of
      objects; as, some lenses magnify but little.
      [1913 Webster]

   2. To have effect; to be of importance or significance. [Cant
      & Obs.] --Spectator.
      [1913 Webster]

WordNet (r) 3.0 (2006):

magnify
    v 1: increase in size, volume or significance; "Her terror was
         magnified in her mind" [syn: magnify, amplify]
    2: to enlarge beyond bounds or the truth; "tended to romanticize
       and exaggerate this `gracious Old South' imagery" [syn:
       overstate, exaggerate, overdraw, hyperbolize,
       hyperbolise, magnify, amplify] [ant: downplay,
       minimise, minimize, understate]
    3: make large; "blow up an image" [syn: blow up, enlarge,
       magnify] [ant: reduce, scale down]

Moby Thesaurus II by Grady Ward, 1.0:

167 Moby Thesaurus words for "magnify":
   accelerate, add to, adulate, agent provocateur, aggrandize,
   aggravate, amplify, annoy, apotheose, apotheosize, augment,
   ballyhoo, beatify, beef up, belaud, bepraise, bless,
   bless the Lord, bloat, blow up, boast of, boost, brag about,
   broaden, build, build up, bulk, bulk out, burlesque, canonize,
   caricature, carry too far, celebrate, color, complicate,
   concentrate, condense, consolidate, crescendo, crown, cry up,
   deepen, deify, deteriorate, develop, dignify, dilate, distend,
   distinguish, double, doxologize, dramatize, draw the longbow,
   elevate, embellish, embitter, emblazon, enhance, enlarge, ennoble,
   enshrine, enthrone, erect, eulogize, exacerbate, exaggerate, exalt,
   exasperate, expand, extend, extol, flatter, fudge, glamorize,
   glorify, glorify the Lord, go to extremes, heat up, heighten,
   hero-worship, hike, hike up, honor, hop up, hot up, huff, hymn,
   hyperbolize, idolize, immortalize, increase, inflate, intensify,
   irritate, jazz up, key up, laud, lay it on, lionize, make acute,
   make complex, make legendary, make much of, make worse, maximize,
   mount, multiply, overcharge, overdo, overdraw, overemphasize,
   overestimate, overpaint, overpraise, overreach, overreact,
   oversell, overspeak, overstate, overstress, pad, panegyrize,
   pay tribute, pile it on, porter aux nues, praise, praise God,
   provoke, puff, puff up, pump, pump up, raise, ramify, rarefy,
   redouble, reinforce, rouse, saint, salute, sanctify, set up,
   sharpen, sing praises, soup up, sour, step up, strengthen, stretch,
   stretch the truth, sublime, sufflate, swell, talk big,
   talk in superlatives, throne, tout, travesty, triple, trumpet, up,
   uplift, uprear, vise, whet, widen, worsen