The Collaborative International Dictionary of English v.0.48:

Directly \Di*rect"ly\, adv.
   1. In a direct manner; in a straight line or course. "To run
      directly on." --Shak.
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            Indirectly and directly too
            Thou hast contrived against the very life
            Of the defendant.                     --Shak.
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   2. In a straightforward way; without anything intervening;
      not by secondary, but by direct, means.
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   3. Without circumlocution or ambiguity; absolutely; in
      express terms.
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            No man hath hitherto been so impious as plainly and
            directly to condemn prayer.           --Hooker.
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   4. Exactly; just.
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            Stand you directly in Antonius' way.  --Shak.
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   5. Straightforwardly; honestly.
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            I have dealt most directly in thy affair. --Shak.
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   6. Manifestly; openly. [Obs.]
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            Desdemona is directly in love with him. --Shak.
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   7. Straightway; next in order; without delay; immediately.
      "Will she go now to bed?' ?Directly.'" --Shak.
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   8. Immediately after; as soon as.
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            Directly he stopped, the coffin was removed.
                                                  --Dickens.
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   Note: This use of the word is common in England, especially
         in colloquial speech, but it can hardly be regarded as
         a well-sanctioned or desirable use.
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   Directly proportional (Math.), proportional in the order of
      the terms; increasing or decreasing together, and with a
      constant ratio; -- opposed to inversely proportional.

   Syn: Immediately; forthwith; straightway; instantly;
        instantaneously; soon; promptly; openly; expressly.

   Usage: -- Directly, Immediately, Instantly,
          Instantaneously. Directly denotes, without any delay
          or diversion of attention; immediately implies,
          without any interposition of other occupation;
          instantly implies, without any intervention of time.
          Hence, "I will do it directly," means, "I will go
          straightway about it." "I will do it immediately,"
          means, "I will do it as the very next thing." "I will
          do it instantly," allows not a particle of delay.
          Instantaneously, like instantly, marks an interval too
          small to be appreciable, but commonly relates to
          physical causes; as, the powder touched by fire
          instantaneously exploded.
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WordNet (r) 3.0 (2006):

directly
    adv 1: without deviation; "the path leads directly to the lake";
           "went direct to the office" [syn: directly, straight,
           direct]
    2: without anyone or anything intervening; "these two factors
       are directly related"; "he was directly responsible";
       "measured the physical properties directly"
    3: without delay or hesitation; with no time intervening; "he
       answered immediately"; "found an answer straightaway"; "an
       official accused of dishonesty should be suspended
       forthwith"; "Come here now!" [syn: immediately,
       instantly, straightaway, straight off, directly,
       now, right away, at once, forthwith, like a shot]
    4: in a forthright manner; candidly or frankly; "he didn't
       answer directly"; "told me straight out"; "came out flat for
       less work and more pay" [syn: directly, flat, straight]
       [ant: indirectly]

Moby Thesaurus II by Grady Ward, 1.0:

122 Moby Thesaurus words for "directly":
   PDQ, absolutely, after a while, all joking aside, anon, apace,
   at once, before long, betimes, bluffly, bluntly, broadly,
   brusquely, by and by, candidly, completely, dead, dead ahead,
   decisively, definitely, direct, down the alley, due, due north,
   entirely, ere long, even, exactly, expeditiously, expressly,
   faithfully, forthright, forthwith, frankly, genuinely, immediately,
   in a beeline, in a moment, in a while, in all conscience,
   in all respects, in all seriousness, in due course, in due time,
   in every respect, in line with, in no time, in plain English,
   in plain words, instanter, instantly, ipsissimis verbis, just,
   literally, literatim, momentarily, naturally, on the beam,
   on the instant, on the spot, on the straight, openheartedly,
   openly, outspokenly, plain-spokenly, plainly, plumb, point-blank,
   positively, precisely, presently, pretty damned quick, promptly,
   pronto, quickly, right, right away, right off, rigidly, rigorously,
   roundly, shortly, sincerely, smartly, soon, speedily, square,
   squarely, straight, straight across, straight ahead, straightaway,
   straightforward, straightforwardly, straightforwards, straightly,
   straightway, strictly, subito, summarily, swiftly, to the letter,
   unaffectedly, unassumingly, unconstrainedly, undeviatingly,
   unerringly, unpretentiously, unreservedly, unrestrainedly,
   unswervingly, unveeringly, verbally, verbatim,
   verbatim et litteratim, when, with all speed, with no nonsense,
   without delay, without further delay, word by word,
   word for word