heavyweight
     adj : heaviest in a category or of a heavyweight category (more
           than 190 pounds for prizefighters); "a heavyweight
           boxer"
     n 1: an amateur boxer who weighs no more than 201 pounds
     2: a wrestler who weighs more than 214 pounds
     3: a professional boxer who weighs more than 190 pounds
     4: a very large person; impressive in size or qualities [syn: {giant},
         {hulk}, {whale}]
     5: a person of exceptional importance and reputation [syn: {colossus},
         {behemoth}, {giant}, {titan}]
Source: WordNet® 2.0

heavyweight adj. [common] High-overhead; {baroque}; code-intensive;
   featureful, but costly. Esp. used of communication protocols, language
   designs, and any sort of implementation in which maximum generality
   and/or ease of implementation has been pushed at the expense of mundane
   considerations such as speed, memory utilization, and startup time.
   {EMACS} is a heavyweight editor; {X} is an _extremely_ heavyweight
   window system. This term isn't pejorative, but one hacker's heavyweight
   is another's {elephantine} and a third's {monstrosity}. Oppose
   `lightweight'. Usage: now borders on techspeak, especially in the
   compound `heavyweight process'.


Source: The Jargon File