[1] : The Collaborative International Dictionary of English v.0.48

tweak \tweak\, n.
   1. a sharp pinch or jerk; a twist or twitch; as, a tweak of
      the nose. --swift.
      1913 webster

   2. trouble; distress; tweag. obs.
      1913 webster

   3. a prostitute. obs. --brathwait.
      1913 webster

[2] : The Collaborative International Dictionary of English v.0.48

tweak \tweak\, v. t. oe. twikken, originally the same word as
   twicchen; cf. lg. twikken. see twitch.
   to pinch and pull with a sudden jerk and twist; to twitch;
   as, to tweak the nose. --shak.
   1913 webster
see also:
twitch 

[3] : WordNet (r) 2.0

tweak
     n : a squeeze with the fingers syn: pinch
     v 1: pinch or squeeze sharply
     2: pull or pull out sharply; "pluck the flowers off the bush"
        syn: pluck, pull off, pick off
     3: adjust finely; "fine-tune the engine" syn: fine-tune
see also:
pinch pluck pull off pick off fine-tune 

[4] : Moby Thesaurus II by Grady Ward, 1.0

111 moby thesaurus words for "tweak":
   acute pain, afflict, agonize, ail, bite, bob, boring pain, burn,
   chafe, charley horse, clamp, clamping, clamping down, compress,
   compression, convulse, cramp, cramps, crick, crucify, crush, cut,
   darting pain, distress, ensphere, excruciate, fester, flick, flip,
   flirt, flounce, fret, fulgurant pain, gall, girdle pain, give pain,
   gnaw, gnawing, grate, grind, grip, gripe, griping, harrow, hitch,
   hurt, inflame, inflict pain, irritate, jerk, jig, jigger, jigget,
   jiggle, jog, joggle, jumping pain, kill by inches, kink, lacerate,
   lancinating pain, martyr, martyrize, nip, pain, pang, paroxysm,
   pierce, pinch, pluck, press, pressure, prick, prolong the agony,
   put to torture, rack, rankle, rasp, rub, seizure, sharp pain,
   shoot, shooting, shooting pain, snake, snatch, spasm, squeeze,
   squeezing, stab, stabbing pain, start, sting, stitch, sudden pull,
   thrill, throes, tighten, tightening, tormen, torment, torture,
   twinge, twist, twitch, wad up, wound, wrench, wring, yank, yerk

[5] : Jargon File (4.3.1, 29 Jun 2001)

tweak vt. 1. to change slightly, usually in reference to a value. also
   used synonymously with twiddle. if a program is almost correct, rather
   than figure out the precise problem you might just keep tweaking it
   until it works. see frobnicate and fudge factor; also see shotgun
   debugging. 2. to tune or bum a program; preferred usage in the u.k.


see also:
twiddle frobnicate fudge factor shotgun debugging tune bum 

[6] : The Free On-line Dictionary of Computing (27 SEP 03)

tweak
     
        1. to change slightly, usually in reference to a value.  also
        used synonymously with twiddle.  if a program is almost
        correct, rather than figure out the precise problem you might
        just keep tweaking it until it works.  see frobnicate and
        fudge factor; also see shotgun debugging.
     
        2. to tune or bum a program; preferred usage in the uk.
     
        jargon file
     
     
see also:
twiddle frobnicate fudge factor shotgun debugging tune bum 
jargon file 

Tweak >> T Words
Tweak, definition of term: Tweak
tweak_pag1.html