Definition of "blacken" [black•en]

• To make black. (verb-transitive)
• To sully or defame: a scandal that blackened the mayor's name. (verb-transitive)
• To coat (fish or meat, for example) with pepper and other spices and then quickly sear in a very hot skillet, thereby producing meat that is black on the outside but tender on the inside. (verb-transitive)
• To become dark or black: The day blackened into night. (verb-intransitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Although there are two distinct schools of thought on grilled chicken, one that advocates par boiling and one that does not, Mexican cooks do not par boil and are not afraid to let the chicken skin blacken on the outside while the chicken cooks through."
• "No doubt the Clinton campaign wants to "blacken" Obama however they can, but do they really want to make Clinton the candidate of the loony racist wing of the Democratic party?"
• "I've just found another person asserting that maybe -- just maybe -- we should have something approaching conclusive evidence before alleging that the Clintons hatched a dastardly and bigoted scheme to "blacken" Obama and provoke a white backlash."