The Collaborative International Dictionary of English v.0.48:

Weakling \Weak"ling\, n. [Weak + -ling.]
   A weak or feeble creature. --Shak. "All looking on him as a
   weakling, which would post to the grave." --Fuller.
   [1913 Webster]

         We may not be weaklings because we have a strong enemy.
                                                  --Latimer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Weakling \Weak"ling\, a.
   Weak; feeble. --Sir T. North.
   [1913 Webster]

WordNet (r) 3.0 (2006):

weakling
    n 1: a person who is physically weak and ineffectual [syn:
         weakling, doormat, wuss]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "weakling":
   Milquetoast, baby, big baby, blank cartridge, butt, castrato,
   chicken, chicken liver, coward, crybaby, doormat, drip, dud,
   dull tool, eunuch, faintly, fence-sitter, fraid-cat, fraidy-cat,
   funk, funker, gelding, gutless wonder, impotent, incompetent,
   invalid, invertebrate, jellyfish, lightweight, lily liver, mark,
   meek soul, milksop, misfit, mollycoddle, mouse, mugwump,
   namby-pamby, nebbish, nonentity, pansy, pantywaist, pushover,
   sad sack, scaredy-cat, shilly-shally, shrinking violet, sissy,
   softling, softy, sop, sotto voce, sucker, waverer, weak sister,
   weakly, white feather, white liver, wobbler