Heavy Hitter Meaning

(idiomatic) A person of considerable importance who is a major decision maker or capable achiever; an especially significant organization or an especially functional object.

Example: 1991 Nov. 20, Claire Smith, "On Baseball: Bonilla Barnstorming In Search of Best Deal," New York Times (retrieved 20 Aug 2014):
  This year's heavy hitter is Bobby Bonilla, the Pirates' slugger who's seeking to hit the biggest home run of his life.
2010 Dec. 30, Associated Press, "MLB Hall of Famer Harmon Killebrew has esophageal cancer," New York Daily News (retrieved 20 Aug 2014):
  The congenial heavy hitter is one of the most beloved players in Twins history, as much for his gentle and approachable nature off the field as for the towering home runs he hit during his playing days.
1967 Nov. 6, Hector (Toe) Blake, "Keep Your Eye On An Exciting Game," Sports Illustrated (retrieved 20 Aug 2014):
  On defense I always try to pair a good body-checker with a sound, steady player; for example, Ted Harris, a heavy hitter, with J. C. Tremblay, a clever defenseman.
2009 July 1, Alan Burge, "Two Texans players on list of the 50 top-earning American athletes," AXS Entertainment Sports (retrieved 20 Aug 2014):
  This is a heavy hitter list including the likes of Tiger Woods, LeBron James, and Alex Rodriguez.
1993 Jan. 28, Rupert Cornwell, "Hillary called to cure ills of US health system," Independent (UK) (retrieved 20 Aug 2014):
  Even Mrs Clinton, the heavy hitter, will need every ounce of her formidable powers.
2013 Feb. 20, Sean Williams, "3 Stocks to Get on Your Watchlist," Seattle Post-Intelligencer (retrieved 20 Aug 2014):
  For Yamana, its El Penon mine in Chile is its heavy hitter, with production expectations of 450,000 to 500,000 ounces per year.
2014 Feb. 15, John L. Allen Jr., "Legionaries are Pope Francis’ problem now," Boston Globe (retrieved 20 Aug 2014):
  Müller used this speech, delivered in the presence of Cardinal Angelo Scola of Milan, another heavy-hitter in the Catholic world, to draw some lines in the sand.