The Collaborative International Dictionary of English v.0.48:

Creep \Creep\ (kr[=e]p), v. t. [imp. Crept (kr[e^]pt) (Crope
   (kr[=o]p), Obs.); p. p. Crept; p. pr. & vb. n. Creeping.]
   [OE. crepen, creopen, AS. cre['o]pan; akin to D. kruipen, G.
   kriechen, Icel. krjupa, Sw. krypa, Dan. krybe. Cf. Cripple,
   Crouch.]
   1. To move along the ground, or on any other surface, on the
      belly, as a worm or reptile; to move as a child on the
      hands and knees; to crawl.
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            Ye that walk
            The earth, and stately tread, or lowly creep.
                                                  --Milton.
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   2. To move slowly, feebly, or timorously, as from
      unwillingness, fear, or weakness.
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            The whining schoolboy . . . creeping, like snail,
            Unwillingly to school.                --Shak.
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            Like a guilty thing, I creep.         --Tennyson.
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   3. To move in a stealthy or secret manner; to move
      imperceptibly or clandestinely; to steal in; to insinuate
      itself or one's self; as, age creeps upon us.
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            The sophistry which creeps into most of the books of
            argument.                             --Locke.
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            Of this sort are they which creep into houses, and
            lead captive silly women.             --2. Tim. iii.
                                                  6.
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   4. To slip, or to become slightly displaced; as, the
      collodion on a negative, or a coat of varnish, may creep
      in drying; the quicksilver on a mirror may creep.
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   5. To move or behave with servility or exaggerated humility;
      to fawn; as, a creeping sycophant.
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            To come as humbly as they used to creep. --Shak.
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   6. To grow, as a vine, clinging to the ground or to some
      other support by means of roots or rootlets, or by
      tendrils, along its length. "Creeping vines." --Dryden.
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   7. To have a sensation as of insects creeping on the skin of
      the body; to crawl; as, the sight made my flesh creep. See
      Crawl, v. i., 4.
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   8. To drag in deep water with creepers, as for recovering a
      submarine cable.
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The Collaborative International Dictionary of English v.0.48:

Creep \Creep\, n.
   1. The act or process of creeping.
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   2. A distressing sensation, or sound, like that occasioned by
      the creeping of insects.
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            A creep of undefinable horror.        --Blackwood's
                                                  Mag.
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            Out of the stillness, with gathering creep,
            Like rising wind in leaves.           --Lowell.
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   3. (Mining) A slow rising of the floor of a gallery,
      occasioned by the pressure of incumbent strata upon the
      pillars or sides; a gradual movement of mining ground.
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WordNet (r) 3.0 (2006):

creep
    n 1: someone unpleasantly strange or eccentric [syn: creep,
         weirdo, weirdie, weirdy, spook]
    2: a slow longitudinal movement or deformation
    3: a pen that is fenced so that young animals can enter but
       adults cannot
    4: a slow mode of locomotion on hands and knees or dragging the
       body; "a crawl was all that the injured man could manage";
       "the traffic moved at a creep" [syn: crawl, crawling,
       creep, creeping]
    v 1: move slowly; in the case of people or animals with the body
         near the ground; "The crocodile was crawling along the
         riverbed" [syn: crawl, creep]
    2: to go stealthily or furtively; "..stead of sneaking around
       spying on the neighbor's house" [syn: sneak, mouse,
       creep, pussyfoot]
    3: grow or spread, often in such a way as to cover (a surface);
       "ivy crept over the walls of the university buildings"
    4: show submission or fear [syn: fawn, crawl, creep,
       cringe, cower, grovel]

The Jargon File (version 4.4.7, 29 Dec 2003):

creep
 v.

    To advance, grow, or multiply inexorably. In hackish usage this verb has
    overtones of menace and silliness, evoking the creeping horrors of
    low-budget monster movies.