oppo guynoun.
A political operative who specializes in digging up dirt on opponents.
Example Citation:
"There will be knowing looks all around this town if you proffer a spin about White House oppo guys who dug up dish and Borked political opponents to counter the right-wing hitmen who are sliming the president."
David Goldstein, "Washington-Speak Evidence of Sheltered Life in Capital," The Arizona Replublic