The Collaborative International Dictionary of English v.0.48:

Sesquipedal \Ses*quip"e*dal\, Sesquipedalian
\Ses`qui*pe*da"li*an\, a. [Sesqui- + pedal: cf. F.
   sesquip['e]dal, L. sesquipedalis.]
   Measuring or containing a foot and a half; as, a
   sesquipedalian pygmy; -- sometimes humorously applied to long
   words.
   [1913 Webster]
   [1913 Webster] Sesquipedalianism

WordNet (r) 3.0 (2006):

sesquipedalian
    adj 1: given to the overuse of long words; "sesquipedalian
           orators"; "this sesquipedalian way of saying one has no
           money"
    2: (of words) long and ponderous; having many syllables;
       "sesquipedalian technical terms" [syn: polysyllabic,
       sesquipedalian]
    n 1: a very long word (a foot and a half long) [syn:
         sesquipedalian, sesquipedalia]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "sesquipedalian":
   Latinate, a mile long, awkward, bombastic, cramped, cumbrous,
   elephantine, extensive, far-flung, far-reaching, fargoing, forced,
   formal, grandiloquence, guinde, halting, hard word, heavy, inkhorn,
   interminable, jawbreaker, jawbreaking, labored, leaden, lengthy,
   lexiphanicism, long, long word, longish, longsome, lumbering,
   no end of, polysyllabic, polysyllable, pompous, ponderous,
   sesquipedal, stiff, stilted, tall, turgid, unwieldy, without end