The Collaborative International Dictionary of English v.0.48:

Cloy \Cloy\ (kloi), v. t. [imp. & p. p. Cloyed (kloid); p. pr.
   & vb. n. Cloying.] [OE. cloer to nail up, F. clouer, fr.
   OF. clo nail, F. clou, fr. L. clavus nail. Cf. 3d Clove.]
   1. To fill or choke up; to stop up; to clog. [Obs.]
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            The duke's purpose was to have cloyed the harbor by
            sinking ships, laden with stones.     --Speed.
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   2. To glut, or satisfy, as the appetite; to satiate; to fill
      to loathing; to surfeit.
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            [Who can] cloy the hungry edge of appetite
            By bare imagination of a feast?       --Shak.
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            He sometimes cloys his readers instead of
            satisfying.                           --Dryden.
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   3. To penetrate or pierce; to wound.
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            Which, with his cruel tusk, him deadly cloyed.
                                                  --Spenser.
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            He never shod horse but he cloyed him. --Bacon.
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   4. To spike, as a cannon. [Obs.] --Johnson.
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   5. To stroke with a claw. [Obs.] --Shak.
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WordNet (r) 3.0 (2006):

cloying
    adj 1: overly sweet [syn: cloying, saccharine, syrupy,
           treacly]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "cloying":
   bad, barfy, bathetic, beery, brackish, cloysome, fetid, filling,
   foul, fulsome, gooey, gushing, high, icky, jading, luscious,
   maggoty, maudlin, mawkish, mushy, namby-pamby, nasty, nauseant,
   nauseating, nauseous, noisome, nostalgic, nostomanic, noxious,
   offensive, overfilling, overripe, oversentimental,
   oversentimentalized, oversweet, poisonous, rancid, rank,
   rebarbative, rich, romantic, rotten, saccharine, sappy, satiating,
   sating, satisfying, sentimental, sentimentalized, sickening,
   sickly-sweet, sloppy, soft, spoiled, sticky, stinking, surfeiting,
   tear-jerking, teary, vile, vomity, weevily, yucky