The Collaborative International Dictionary of English v.0.48:

Lank \Lank\ (l[a^][ng]k), a. [Compar. Lanker; superl.
   Lankest.] [AS. hlanc; cf. G. lenken to turn, gelenk
   joint, OHG. hlanca hip, side, flank, and E. link of a chain.]
   1. Slender and thin; not well filled out; not plump;
      shrunken; lean.
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            Meager and lank with fasting grown.   --Swift.
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            Who would not choose . . . to have rather a lank
            purse than an empty brain?            --Barrow.
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   2. Languid; drooping. [Obs.]
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            Who, piteous of her woes, reared her lank head.
                                                  --Milton.
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   Lank hair, long, thin hair. --Macaulay.
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