The Collaborative International Dictionary of English v.0.48:

Cub \Cub\ (k[u^]b), n. [Cf. Ir. cuib cub, whelp, young dog, Ir.
   & Gael. cu dog; akin to E. hound.]
   1. A young animal, esp. the young of the bear.
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   2. Jocosely or in contempt, a boy or girl, esp. an awkward,
      rude, ill-mannered boy.
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            O, thou dissembling cub! what wilt thou be
            When time hath sowed a grizzle on thy case? --Shak.
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The Collaborative International Dictionary of English v.0.48:

Cub \Cub\, v. t. & i. [imp. & p. p. Cubbed (k[u^]bd); p. pr. &
   vb. n. Cubbing.]
   To bring forth; -- said of animals, or in contempt, of
   persons. "Cubb'd in a cabin." --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cub \Cub\, n. [Cf. Cub a young animal.]
   1. A stall for cattle. [Obs.]
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            I would rather have such . . . .in cub or kennel
            than in my closet or at my table.     --Landor.
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   2. A cupboard. [Obs.] --Laud.
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The Collaborative International Dictionary of English v.0.48:

Cub \Cub\, v. t.
   To shut up or confine. [Obs.] --Burton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cub
    n 1: an awkward and inexperienced youth [syn: cub,
         greenhorn, rookie]
    2: a male child (a familiar term of address to a boy) [syn:
       cub, lad, laddie, sonny, sonny boy]
    3: the young of certain carnivorous mammals such as the bear or
       wolf or lion [syn: cub, young carnivore]
    v 1: give birth to cubs; "bears cub every year"

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "cub":
   birdling, boy, bub, bubba, buck, bud, buddy, calf, catling, chick,
   chickling, chicky, colt, dogie, duckling, fawn, fellow, fledgling,
   foal, fryer, gosling, hobbledehoy, kid, kit, kitten, lad, laddie,
   lamb, lambkin, litter, manchild, master, muchacho, nest, nestling,
   piglet, pigling, polliwog, pullet, pup, puppy, schoolboy, shoat,
   sonny, sonny boy, tadpole, weaner, whelp, yeanling, young man,
   youth