The phrase "tireless champion" means someone who tirelessly and continuously supports and fights for a cause or person. They do not give up easily and work hard to achieve their goals. Full definition
Each of the exemplary programs benefited from a core team of leaders who acted as tireless champions for the program. (wallacefoundation.org)
On June 1st, 2012, Maria Gunnoe, 2009 Goldman Environmental Prize winner and tireless champion of Appalachian environmental and human rights, arrived at the Capitol building in Washington, DC. (goldmanprize.org)
Beautiful Sarah is currently in foster care with an employee of Lucky Paws, whose mission is to «serve as tireless champions for the animals of Albuquerque by providing them the finest care available along with hands - on assistance in finding happy homes.» (shelterme.tv)