The Collaborative International Dictionary of English v.0.48:

Tickle \Tic"kle\, a.
   1. Ticklish; easily tickled. [Obs.]
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   2. Liable to change; uncertain; inconstant. [Obs.]
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            The world is now full tickle, sikerly. --Chaucer.
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            So tickle is the state of earthy things. --Spenser.
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   3. Wavering, or liable to waver and fall at the slightest
      touch; unstable; easily overthrown. [Obs.]
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            Thy head stands so tickle on thy shoulders, that a
            milkmaid, if she be in love, may sigh it off.
                                                  --Shak.
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The Collaborative International Dictionary of English v.0.48:

Tickle \Tic"kle\, v. t. [imp. & p. p. Tickled; p. pr. & vb. n.
   Tickling.] [Perhaps freq. of tick to beat; pat; but cf.
   also AS. citelian to tickle, D. kittelen, G. kitzlen, OHG.
   chizzil[=o]n, chuzzil[=o]n, Icel. kitla. Cf. Kittle, v. t.]
   1. To touch lightly, so as to produce a peculiar thrilling
      sensation, which commonly causes laughter, and a kind of
      spasm which become dangerous if too long protracted.
      [1913 Webster]

            If you tickle us, do we not laugh?    --Shak.
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   2. To please; to gratify; to make joyous.
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            Pleased with a rattle, tickled with a straw. --Pope.
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            Such a nature
            Tickled with good success, disdains the shadow
            Which he treads on at noon.           --Shak.
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The Collaborative International Dictionary of English v.0.48:

Tickle \Tic"kle\, v. i.
   1. To feel titillation.
      [1913 Webster]

            He with secret joy therefore
            Did tickle inwardly in every vein.    --Spenser.
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   2. To excite the sensation of titillation. --Shak.
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WordNet (r) 3.0 (2006):

tickle
    n 1: a cutaneous sensation often resulting from light stroking
    2: the act of tickling [syn: tickle, tickling,
       titillation]
    v 1: touch (a body part) lightly so as to excite the surface
         nerves and cause uneasiness, laughter, or spasmodic
         movements [syn: tickle, titillate, vellicate]
    2: feel sudden intense sensation or emotion; "he was thrilled by
       the speed and the roar of the engine" [syn: thrill,
       tickle, vibrate]
    3: touch or stroke lightly; "The grass tickled her calves"

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "tickle":
   affect the interest, agitate, amuse, appeal, arouse, attract,
   be attractive, beak, becharm, beckon, beguile, bewitch,
   blow the coals, brush, bunt, captivate, carry away, charm, chuck,
   concern, convulse, dab, delectate, delight, divert, enchant,
   engage, enliven, enrapture, enravish, entertain, enthrall,
   entrance, excite, excite interest, exhilarate, fan, fan the flame,
   fascinate, feed the fire, ferment, fetch, fillip, fire, flick,
   flip, flirt, flush, foment, fracture one, freak out, give a thrill,
   gratify, graze, heat, heat up, imparadise, impassion, incense,
   incite, inflame, instigate, interest, intoxicate, invite,
   involve in, kill, knock dead, knock out, loosen up, nettle, pat,
   peck, pick, pique, pleasant stimulation, please, provoke,
   put up to, raise a laugh, raise a smile, rally, rap, ravish,
   recreate, refresh, regale, relax, send, set on, sic on, slay, snap,
   solace, stimulate, stir the embers, stir up, summon, tantalize,
   tap, tease, tempt, thrill, tickle pink, tickliness, tickling,
   ticklishness, tip, titillate, titillation, touch, transport, whet,
   whet the appetite, whip up, whisk, work up, wow



The Free On-line Dictionary of Computing (30 December 2018):

Tickle

    A text editor, file translator and TCL
   interpreter for the Macintosh.

   Version 5.0v1.  The text editor breaks the 32K limit (like
   MPW).

   The file translation utilities support drag and drop
   handling via tcl scripts of BinHex, MacBinary, Apple
   Computer Single/Double, StuffIt (with engine), Unix
   compress, Unix tar and UUencode files as well as text
   translation.

   Tickle implements tcl 7.0 with tclX extensions and
   Macintosh equivalents of Unix's ls, pwd, cd
   commands.  It provides Macintosh access to Resource Manager,
   Communications Toolbox, OSA Components (and
   AppleScript), Editions (publish and subscribe) and Apple
   Events (including AEBuild and AEPrint).  OSA Script support
   allows programming of any OSA scripting component within
   Tickle interpreter windows.  It provides the OSAtcl and OSAJ
   J/APL extensions and creates "Ticklets" which are small
   application programs that carry only the tcl script and use
   code in the OSAtcl component to drive an application that
   allows drag and drop with tcl scripts.  Tickle is scriptable
   and recordable.

   (ftp://ftp.msen.com/pub/vendor/ice/tickle/Tickle5.0v1.hqx).

   E-mail: .

   (1994-10-12)