What is the meaning of Muckrake?

(v.i.) To seek for, expose or charge, especially habitually, corruption, real or alleged, on the part of public men and corporations. On April 14, 1906, President Roosevelt delivered a speech on "The Man with the Muck Rake," in which he deprecated sweeping and unjust charges of corruption against public men and corporations. The phrase was taken up by the press, and the verb to muck"rake`, in the above sense, and the noun muck"rak`er (/), to designate one so engaged, were speedily coined and obtained wide currency. The original allusion was to a character in Bunyan's "Pilgrim's Progress" so intent on raking up muck that he could not see a celestial crown held above him.