The Collaborative International Dictionary of English v.0.48:

Loiter \Loi"ter\, v. i. [imp. & p. p. Loitered; p. pr. & vb.
   n. Loitering.] [D. leuteren to delay, loiter; cf; Prov. G.
   lottern to be louse, lotter louse, slack, unsettled, vagrant,
   OHG. lotar.]
   1. To be slow in moving; to delay; to linger; to be dilatory;
      to spend time idly; to saunter; to lag behind.
      [1913 Webster]

            Sir John, you loiter here too long.   --Shak.
      [1913 Webster]

            If we have loitered, let us quicken our pace.
                                                  --Rogers.
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   2. To wander as an idle vagrant. [Obs.] --Spenser.

   Syn: To linger; delay; lag; saunter; tarry.
        [1913 Webster]

WordNet (r) 3.0 (2006):

loiter
    v 1: be about; "The high school students like to loiter in the
         Central Square"; "Who is this man that is hanging around
         the department?" [syn: loiter, lounge, footle,
         lollygag, loaf, lallygag, hang around, mess
         about, tarry, linger, lurk, mill about, mill
         around]