The Collaborative International Dictionary of English v.0.48:

Con- \Con-\
   A prefix, fr. L. cum, signifying with, together, etc. See
   Com-.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Con \Con\, adv. [Abbrev. from L. contra against.]
   Against the affirmative side; in opposition; on the negative
   side; -- The antithesis of pro, and usually in connection
   with it. See Pro.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Con \Con\, v. t. [imp. & p. p. Conned; p. pr. & vb. n.
   Conning.] [AS. cunnan to know, be able, and (derived from
   this) cunnian to try, test. See Can, v. t. & i.]
   1. To know; to understand; to acknowledge. [Obs.]
      [1913 Webster]

            Of muses, Hobbinol, I con no skill.   --Spenser.
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            They say they con to heaven the highway. --Spenser.
      [1913 Webster]

   2. To study in order to know; to peruse; to learn; to commit
      to memory; to regard studiously.
      [1913 Webster]

            Fixedly did look
            Upon the muddy waters which he conned
            As if he had been reading in a book.  --Wordsworth.
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            I did not come into Parliament to con my lesson.
                                                  --Burke.
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   To con answer, to be able to answer. [Obs.]

   To con thanks, to thank; to acknowledge obligation. [Obs.]
      --Shak.
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The Collaborative International Dictionary of English v.0.48:

Con \Con\, v. t. [See Cond.] (Naut.)
   To conduct, or superintend the steering of (a vessel); to
   watch the course of (a vessel) and direct the helmsman how to
   steer.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

212 Moby Thesaurus words for "con":
   POW, adversary, adversative, adverse, against, alien, antagonistic,
   anti, antipathetic, antithetic, argue into, argument, argumentum,
   aye, beat, beguile of, bilk, bone, bring over, bring round,
   bring to reason, bunco, burn, cageling, captivate, captive, case,
   chain gang, charm, cheat, chisel, chouse, chouse out of, clashing,
   cog, cog the dice, commit to memory, competitive, conflicting,
   cons, consideration, contemplate, contradictory, contrary, convict,
   convince, counter, cozen, crib, cross, defraud, detenu, diddle,
   dig, disaccordant, disappointed, disapprobatory, disapproving,
   discontented, disenchanted, disgruntled, disillusioned, displeased,
   dissatisfied, dissentient, dissenting, do in, do out of, draw over,
   drill, elenchus, elucubrate, enemy, euchre, ex-convict, examine,
   finagle, flam, fleece, flimflam, fob, fractious, fudge, gain,
   gain over, gaolbird, get by heart, get letter-perfect, go over,
   gouge, grind, gull, gyp, have, have by heart, hocus, hocus-pocus,
   hook, hook in, hostile, ignoratio elenchi, indignant, inimical,
   interest, internee, jailbird, know by heart, learn by heart,
   learn verbatim, lifer, low, lucubrate, memorize, mulct, nay,
   negative, no, noncooperative, obstinate, opponent, opposed,
   opposing, opposite, oppositional, oppositive, oppugnant, outtalk,
   overthwart, pack the deal, parolee, parrot, persuade, peruse,
   perverse, pigeon, plaidoyer, plea, pleading, plunge into,
   political prisoner, poor, pore over, practice, practice fraud upon,
   prevail on, prevail upon, prevail with, prisoner, prisoner of war,
   pro, pros, pros and cons, read, reason, recalcitrant, recite,
   refractory, refutation, regard studiously, repeat, repeat by heart,
   repugnant, restudy, review, rival, rook, scam, screw, sell,
   sell gold bricks, sell one on, shave, shortchange, side,
   special pleading, stack the cards, stick, sting, stir bird, study,
   sway, swindle, swot, swot up, take a dive, talk into, talk over,
   talking point, the affirmative, the negative, thimblerig,
   throw a fight, ticket-of-leave man, ticket-of-leaver, trusty,
   turned-off, unappreciative, unapproving, uncomplimentary,
   uncooperative, unfavorable, unfriendly, unhappy, unpropitious, vet,
   victimize, wade through, wangle, wangle into, wear down, win,
   win over