The Collaborative International Dictionary of English v.0.48:

Congest \Con*gest"\, v. t. [L. congestus, p. p. of congere to
   bring together; con- + gerere. See Gerund.]
   [1913 Webster]
   1. To collect or gather into a mass or aggregate; to bring
      together; to accumulate.
      [1913 Webster]

            To what will thy congested guilt amount?
                                                  --Blackmore.
      [1913 Webster]

   2. (Med.) To cause an overfullness of the blood vessels (esp.
      the capillaries) of an organ or part.
      [1913 Webster]

WordNet (r) 3.0 (2006):

congest
    v 1: become or cause to become obstructed; "The leaves clog our
         drains in the Fall"; "The water pipe is backed up" [syn:
         clog, choke off, clog up, back up, congest,
         choke, foul] [ant: unclog]