The Collaborative International Dictionary of English v.0.48:

Plug \Plug\, v. t. [imp. & p. p. Plugged; p. pr. & vb. n.
   Plugging.]
   To stop with a plug; to make tight by stopping a hole.
   [1913 Webster]

   2. To briefly publicize or advertise, especially during a
      public event not specifically intended for advertising
      purposes; as, during the interview he plugged his new
      book.

   Syn: put in a plug for.
        [PJC]

WordNet (r) 3.0 (2006):

plugged
    adj 1: (of a coin) altered by the insertion of a plug of base
           metal
    2: completely obstructed or closed off; "the storm was
       responsible for many blocked roads and bridges"; "the drain
       was plugged" [syn: blocked, plugged]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "plugged":
   blocked, bound, choked, choked up, clogged, clogged up, congested,
   constipated, costive, foul, fouled, full, infarcted, jammed,
   obstipated, obstructed, packed, plugged up, stopped, stopped up,
   stuffed, stuffed up