Here's some information about another put down word that Imus uttered during that infamous radio program-jigaboo:

The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.

jigaboo

SYLLABICATION: jig·a·boo
PRONUNCIATION:   jg-b
NOUN: Offensive Slang Used as a disparaging term for a Black person.
ETYMOLOGY: Origin unknown

http://www.bartleby.com/61/12/J0041275.html

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Clarence Major's 1994 book "Juba To Jive" has this entry for "jigaboo" :

Jiggabool jigaboo n {163os-1950s} tshikabo {Banto}means a meek or servile person; a very dark skinned African American of pure African descent; a slave term, it was always pejorative [p. 258]