The Collaborative International Dictionary of English v.0.48:

Wench \Wench\ (w[e^]nch), v. i. [imp. & p. p. Wenched
   (w[e^]ncht); p. pr. & vb. n. Wenching.]
   To frequent the company of wenches, or women of ill fame.
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The Collaborative International Dictionary of English v.0.48:

Wench \Wench\ (w[e^]nch), n. [OE. wenche, for older wenchel a
   child, originally, weak, tottering; cf. AS. wencle a maid, a
   daughter, wencel a pupil, orphan, wincel, winclu, children,
   offspring, wencel weak, wancol unstable, OHG. wanchol;
   perhaps akin to E. wink. See Wink.]
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   1. A young woman; a girl; a maiden. --Shak.
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            Lord and lady, groom and wench.       --Chaucer.
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            That they may send again
            My most sweet wench, and gifts to boot. --Chapman.
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            He was received by the daughter of the house, a
            pretty, buxom, blue-eyed little wench. --W. Black.
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   2. A low, vicious young woman; a drab; a strumpet.
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            She shall be called his wench or his leman.
                                                  --Chaucer.
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            It is not a digression to talk of bawds in a
            discourse upon wenches.               --Spectator.
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   3. A colored woman; a negress. [Archaic, U. S.]
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WordNet (r) 3.0 (2006):

wench
    n 1: informal terms for a (young) woman [syn: dame, doll,
         wench, skirt, chick, bird]
    v 1: frequent prostitutes