The Collaborative International Dictionary of English v.0.48:

Launch \Launch\, v. i.
   To move with force and swiftness like a sliding from the
   stocks into the water; to plunge; to make a beginning; as, to
   launch into the current of a stream; to launch into an
   argument or discussion; to launch into lavish expenditures;
   -- often with out.
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         Launch out into the deep, and let down your nets for a
         draught.                                 --Luke v. 4.
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         He [Spenser] launches out into very flowery paths.
                                                  --Prior.
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The Collaborative International Dictionary of English v.0.48:

Launch \Launch\ (l[add]nch or l[aum]nch), v. i. [imp. & p. p.
   Launched (l[add]ncht or l[aum]ncht); p. pr. & vb. n.
   Launching.] [OE. launchen to throw as a lance, OF.
   lanchier, another form of lancier, F. lancer, fr. lance
   lance. See Lance.] [Written also lanch.]
   1. To throw, as a lance or dart; to hurl; to let fly.
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   2. To strike with, or as with, a lance; to pierce. [Obs.]
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            Launch your hearts with lamentable wounds.
                                                  --Spenser.
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   3. To cause to move or slide from the land into the water; to
      set afloat; as, to launch a ship.
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            With stays and cordage last he rigged the ship,
            And rolled on levers, launched her in the deep.
                                                  --Pope.
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   4. To send out; to start (one) on a career; to set going; to
      give a start to (something); to put in operation; as, to
      launch a son in the world; to launch a business project or
      enterprise.
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            All art is used to sink episcopacy, and launch
            presbytery in England.                --Eikon
                                                  Basilike.
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The Collaborative International Dictionary of English v.0.48:

Launch \Launch\, n.
   1. The act of launching.
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   2. The movement of a vessel from land into the water;
      especially, the sliding on ways from the stocks on which
      it is built.
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   3. [Cf. Sp. lancha.] (Naut.) The boat of the largest size
      belonging to a ship of war; also, an open boat of any size
      driven by steam, naphtha, electricity, or the like.
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   Launching ways. (Naut.) See Way, n. (Naut.).
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WordNet (r) 3.0 (2006):

launch
    n 1: a motorboat with an open deck or a half deck
    2: the act of propelling with force [syn: launching, launch]
    v 1: set up or found; "She set up a literacy program" [syn:
         establish, set up, found, launch] [ant: abolish,
         get rid of]
    2: propel with force; "launch the space shuttle"; "Launch a
       ship"
    3: launch for the first time; launch on a maiden voyage; "launch
       a ship"
    4: begin with vigor; "He launched into a long diatribe"; "She
       plunged into a dangerous adventure" [syn: plunge, launch]
    5: get going; give impetus to; "launch a career"; "Her actions
       set in motion a complicated judicial process" [syn: launch,
       set in motion]
    6: smoothen the surface of; "launch plaster"

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "launch":
   advance, altitude peak, automatic control, begin, blast off,
   blast-off, boat, bowl, bring before, bring forward, bring up,
   broach, bundle, bundle off, bung, burn, burnout, cabin cruiser,
   cast, catapult, ceiling, christen, chuck, chunk, commence,
   commend to attention, cruiser, dart, dash, descent, dinghy,
   discharge, dispatch, embark, embark on, embark upon,
   end of burning, establish, fire, flight, fling, flip, float, fork,
   found, get, get going, gig, give a start, heave, hurl, hurtle,
   ignition, impact, inaugurate, inauguration, induct, initiate,
   initiation, install, institute, introduce, jerk, kick off, lance,
   lay before, let fly, lift up, lift-off, lob, make a motion, moot,
   motor launch, motorboat, move, offer a resolution, open, open up,
   opening, organize, originate, pass, peg, pelt, pitch, pitchfork,
   pose, postulate, power cruiser, powerboat, prefer, project,
   propose, proposition, propound, put, put forth, put forward,
   put in motion, put it to, put the shot, raise, recommend, ring in,
   rocket launching, runabout, sedan cruiser, send, send forth,
   send off, serve, set afloat, set agoing, set before, set forth,
   set going, set in motion, set on foot, set up, shoot, shot, shy,
   skiff, sling, snap, speedboat, start, start going, start off,
   start up, steam launch, submit, suggest, tender, throw, tilt, toss,
   trajectory, turn on, usher in, velocity peak