The Collaborative International Dictionary of English v.0.48:

Suck \Suck\, v. i.
   1. To draw, or attempt to draw, something by suction, as with
      the mouth, or through a tube.
      [1913 Webster]

            Where the bee sucks, there suck I.    --Shak.
      [1913 Webster]

   2. To draw milk from the breast or udder; as, a child, or the
      young of an animal, is first nourished by sucking.
      [1913 Webster]

   3. To draw in; to imbibe; to partake.
      [1913 Webster]

            The crown had sucked too hard, and now, being full,
            was like to draw less.                --Bacon.
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   4. To be objectionable, of very poor quality, or offensive;
      as, telemarketing calls really suck; he's a good actor,
      but his singing sucks. [Colloq.]
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Suck \Suck\ (s[u^]k), v. t. [imp. & p. p. Sucked (s[u^]kt); p.
   pr. & vb. n. Sucking.] [OE. suken, souken, AS. s[=u]can,
   s[=u]gan; akin to D. zuigen, G. saugen, OHG. s[=u]gan, Icel.
   s[=u]ga, sj[=u]ga, Sw. suga, Dan. suge, L. sugere. Cf.
   Honeysuckle, Soak, Succulent, Suction.]
   1. To draw, as a liquid, by the action of the mouth and
      tongue, which tends to produce a vacuum, and causes the
      liquid to rush in by atmospheric pressure; to draw, or
      apply force to, by exhausting the air.
      [1913 Webster]

   2. To draw liquid from by the action of the mouth; as, to
      suck an orange; specifically, to draw milk from (the
      mother, the breast, etc.) with the mouth; as, the young of
      an animal sucks the mother, or dam; an infant sucks the
      breast.
      [1913 Webster]

   3. To draw in, or imbibe, by any process resembles sucking;
      to inhale; to absorb; as, to suck in air; the roots of
      plants suck water from the ground.
      [1913 Webster]

   4. To draw or drain.
      [1913 Webster]

            Old ocean, sucked through the porous globe.
                                                  --Thomson.
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   5. To draw in, as a whirlpool; to swallow up.
      [1913 Webster]

            As waters are by whirlpools sucked and drawn.
                                                  --Dryden.
      [1913 Webster]

   To suck in, to draw into the mouth; to imbibe; to absorb.


   To suck out, to draw out with the mouth; to empty by
      suction.

   To suck up, to draw into the mouth; to draw up by suction
      or absorption.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Suck \Suck\, n.
   1. The act of drawing with the mouth.
      [1913 Webster]

   2. That which is drawn into the mouth by sucking;
      specifically, mikl drawn from the breast. --Shak.
      [1913 Webster]

   3. A small draught. [Colloq.] --Massinger.
      [1913 Webster]

   4. Juice; succulence. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

suck
    n 1: the act of sucking [syn: sucking, suck, suction]
    v 1: draw into the mouth by creating a practical vacuum in the
         mouth; "suck the poison from the place where the snake
         bit"; "suck on a straw"; "the baby sucked on the mother's
         breast"
    2: draw something in by or as if by a vacuum; "Mud was sucking
       at her feet"
    3: attract by using an inexorable force, inducement, etc.; "The
       current boom in the economy sucked many workers in from
       abroad" [syn: suck, suck in]
    4: be inadequate or objectionable; "this sucks!"
    5: provide sexual gratification through oral stimulation [syn:
       fellate, suck, blow, go down on]
    6: take in, also metaphorically; "The sponge absorbs water
       well"; "She drew strength from the minister's words" [syn:
       absorb, suck, imbibe, soak up, sop up, suck up,
       draw, take in, take up]
    7: give suck to; "The wetnurse suckled the infant"; "You cannot
       nurse your baby in public in some places" [syn: breastfeed,
       suckle, suck, nurse, wet-nurse, lactate, give
       suck] [ant: bottlefeed]

Moby Thesaurus II by Grady Ward, 1.0:

133 Moby Thesaurus words for "suck":
   apple-polisher, aspirate, aspiration, ass-licker, backscratcher,
   backslapper, beverage, bib, bleed, bootlick, bootlicker, booze,
   breathe in, broach, brown-nose, brownie, bumper, clawback,
   courtier, creature, cringer, decant, draft, draft off, drain,
   drain the cup, dram, draw, draw from, draw in, draw off, drench,
   drink, drink in, drink off, drink to, drink up, drop, dupe, empty,
   exhaust, fawner, flatterer, flunky, footlicker, gargle, groveler,
   gulp, guzzle, handshaker, helot, imbibe, inhalation, inhale,
   inhalement, inspiration, inspire, instrument, jackal, jigger, jolt,
   kowtower, lackey, lap, led captain, let, let blood, let out,
   libation, lickspit, lickspittle, mealymouth, milk, minion, nip,
   peg, peon, phlebotomize, pipette, pledge, portion, potation,
   potion, pull, pump, pump out, puppet, quaff, reptile, round,
   round of drinks, serf, shot, sip, siphon off, slave, slurp, sniff,
   sniffle, snifter, snort, snuff, snuff in, snuffle, spaniel, spot,
   stooge, suck in, suck out, sucking, suckle, suction, sup, swig,
   swill, sycophant, tap, timeserver, tipple, toad, toadeater, toady,
   toast, tool, toss down, toss off, tot, truckler, tufthunter,
   venesect, wash down, wet, yes-man