The Collaborative International Dictionary of English v.0.48:

Elephantine \El`e*phan"tine\, a. [L. elephantinus of ivory, Gr.
   ?: cf. F. ['e]l['e]phantin.]
   Pertaining to the elephant, or resembling an elephant
   (commonly, in size); hence, huge; immense; heavy; as, of
   elephantine proportions; an elephantine step or tread.
   [1913 Webster]

   Elephantine epoch (Geol.), the epoch distinguished by the
      existence of large pachyderms. --Mantell.

   Elephantine tortoise (Zo["o]l.), a huge land tortoise;
      esp., Testudo elephantina, from islands in the Indian
      Ocean; and T. elephantopus, from the Galapagos Islands.
      Elephantoid

WordNet (r) 3.0 (2006):

elephantine
    adj 1: of great mass; huge and bulky; "a jumbo jet"; "jumbo
           shrimp" [syn: elephantine, gargantuan, giant,
           jumbo]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "elephantine":
   Atlantean, Brobdingnagian, Cyclopean, Gargantuan, Herculean,
   Homeric, Latinate, abysmal, arid, astronomic, awkward, barren,
   blah, blank, bloodless, bombastic, bulky, characterless, clumsy,
   cold, colorless, colossal, cramped, cumbersome, cumbrous, dead,
   dismal, draggy, drearisome, dreary, dry, dryasdust, dull, dusty,
   effete, elephantlike, empty, enormous, epic, etiolated, fade, flat,
   forced, formal, gargantuan, giant, giantlike, gigantic, graceless,
   guinde, halting, heavy, heavy-handed, heroic, ho-hum, hollow, huge,
   hulking, hulky, immense, inane, inexcitable, infinite, inkhorn,
   insipid, jejune, jumbo, labored, leaden, lifeless, low-spirited,
   lubberly, lumbering, lumpish, lumpy, maladroit, mammoth, massive,
   massy, mighty, monster, monstrous, monumental, mountainous, pale,
   pallid, pedestrian, plodding, pointless, poky, pompous, ponderous,
   prodigious, profound, sesquipedalian, slow, solemn, spiritless,
   sterile, stiff, stilted, stodgy, stuffy, stupendous, superficial,
   tasteless, tedious, titanic, towering, tremendous, turgid,
   ungraceful, uninspired, unlively, unwieldy, vapid, vast, wooden



The Jargon File (version 4.4.7, 29 Dec 2003):

elephantine
 adj.

    Used of programs or systems that are both conspicuous hogs (owing perhaps
    to poor design founded on brute force and ignorance) and exceedingly 
    hairy in source form. An elephantine program may be functional and even
    friendly, but (as in the old joke about being in bed with an elephant) it's
    tough to have around all the same (and, like a pachyderm, difficult to
    maintain). In extreme cases, hackers have been known to make trumpeting
    sounds or perform expressive proboscatory mime at the mention of the
    offending program. Usage: semi-humorous. Compare ?has the elephant nature?
    and the somewhat more pejorative monstrosity. See also second-system
    effect and baroque.


The Free On-line Dictionary of Computing (30 December 2018):

elephantine

   Used of programs or systems that are both conspicuous hogs
   (owing perhaps to poor design founded on brute force and
   ignorance) and exceedingly hairy in source form.  An
   elephantine program may be functional and even friendly, but
   (as in the old joke about being in bed with an elephant) it's
   tough to have around all the same (and, like a pachyderm,
   difficult to maintain).  In extreme cases, hackers have been
   known to make trumpeting sounds or perform expressive
   proboscatory mime at the mention of the offending program.
   Usage: semi-humorous.  Compare "has the elephant nature" and
   the somewhat more pejorative monstrosity.  See also
   second-system effect and baroque.

   [Jargon File]