trustbuster
noun
trust·bust·er ˈtrəs(t)-ˌbə-stər 
: one who seeks to break up business trusts
specifically : a federal official who prosecutes trusts under the antitrust laws
trust-busting
ˈtrəs(t)-ˌbə-stiŋ
noun 
Example Sentences
Recent Examples on the Web The original trustbuster himself, Teddy Roosevelt, admonished that size in and of itself is not bad. 
Steve Forbes, Forbes, 9 June 2022 During the next five years, Arnold became the country’s greatest trustbuster, issuing nearly as many indictments as had been brought since the Sherman Act was passed. Dan Kaufman, The New Yorker, 17 Aug. 2021 On the menu today: the Fed’s surprising hawkishness, the FTC’s new trustbuster, the anti-Amazon industry, and an evaluation of Congress’s recent antitrust proposals. Daniel Tenreiro, National Review, 17 June 2021 Europe has led the charge with antitrust investigations, and Margrethe Vestager, the region’s top trustbuster, recently vowed to take a harder line on the companies. David Mccabe, BostonGlobe.com, 29 July 2020 The Competition and Markets Authority, the U.K.’s trustbuster, is getting tougher too. Chris Hughes | Bloomberg, Washington Post, 16 Dec. 2019 In their brief filed with the federal appeals court, the Justice Department lawyers sounded more like corporate defense attorneys than crusading trustbusters. Steven Pearlstein, Washington Post, 19 Dec. 2019 Mergers were looked upon more kindly by trustbusters. The Economist, 19 Sep. 2019 After years of waving through deals, shareholders and trustbusters are now getting testier again. The Economist, 6 July 2019 See More
Steve Forbes, Forbes, 9 June 2022 During the next five years, Arnold became the country’s greatest trustbuster, issuing nearly as many indictments as had been brought since the Sherman Act was passed. Dan Kaufman, The New Yorker, 17 Aug. 2021 On the menu today: the Fed’s surprising hawkishness, the FTC’s new trustbuster, the anti-Amazon industry, and an evaluation of Congress’s recent antitrust proposals. Daniel Tenreiro, National Review, 17 June 2021 Europe has led the charge with antitrust investigations, and Margrethe Vestager, the region’s top trustbuster, recently vowed to take a harder line on the companies. David Mccabe, BostonGlobe.com, 29 July 2020 The Competition and Markets Authority, the U.K.’s trustbuster, is getting tougher too. Chris Hughes | Bloomberg, Washington Post, 16 Dec. 2019 In their brief filed with the federal appeals court, the Justice Department lawyers sounded more like corporate defense attorneys than crusading trustbusters. Steven Pearlstein, Washington Post, 19 Dec. 2019 Mergers were looked upon more kindly by trustbusters. The Economist, 19 Sep. 2019 After years of waving through deals, shareholders and trustbusters are now getting testier again. The Economist, 6 July 2019 See More Word History
First Known Use
1893, in the meaning defined above
Legal Definition
trustbuster
noun
trust·bust·er ˈtrəst-ˌbəs-tər
: one and especially a federal officer who seeks to break up trusts by prosecution under the antitrust laws