The Collaborative International Dictionary of English v.0.48:

crony \cro"ny\ (kr[=o]"n[y^]), n.; pl. Cronies
   (kr[=o]"n[i^]z). [Orig., an old woman. See Crone.]
   1. A crone. [Obs.] "Marry not an old crony." --Burton.
      [1913 Webster]

   2. An intimate companion; a familiar friend. [Colloq.]
      [1913 Webster]

            He soon found his former cronies, though all rather
            the worse for the wear and tear of time. --W.
                                                  Irving.
      [1913 Webster]

WordNet (r) 3.0 (2006):

crony
    n 1: a close friend who accompanies his buddies in their
         activities [syn: buddy, brother, chum, crony,
         pal, sidekick]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "crony":
   ace, adjunct, ally, amigo, associate, bedfellow, bedmate,
   bosom buddy, brother, brother-in-arms, buddy, bunkie, bunkmate,
   butty, camarade, chamberfellow, chum, classmate, coadjutor, cohort,
   colleague, comate, companion, company, compatriot, compeer,
   comrade, confederate, confrere, consociate, consort, copartner,
   fellow, fellow member, fellow student, girl friend, gossip, mate,
   messmate, old crony, pal, pard, pardner, partner, playfellow,
   playmate, roommate, running mate, schoolfellow, schoolmate,
   shipmate, side partner, sidekick, teammate, workfellow, yokefellow,
   yokemate