"Demoncrat” ("demon" + “Democrat,” with capitalization optional) is a derogatory nickname for a member of the Democrat party. “Demoncrat” is cited in print from at least 1992 and has been popularly used on websites and blogs from about 1999.

A similar nickname to “Demoncrat’ is “Demonrat.”


Wiktionary: Demoncrat
Etymology
Blend of demon and democrat
Proper noun
Demoncrat (plural Demoncrats)
(US, slang, pejorative) A member of the Democratic Party (with a demonic implication).

Urban Dictionary
Demoncrat
A liberal Democrat as perceived by a Bible-belt conservative Republican. An amalgamation of the words “demon” and “democrat.”
Only a true demoncrat could be in favor of unrestricted abortions.
by Accu May 29, 2006

21 August 1992, Buffalo (NY) News, Convention Notebook:
One sign that drew attention on the convention floor was “Exorcise the Demoncrats,” held by a traveling evangelist, the Rev. Robert Schenck of the Town of ...

15 July 1995, Wichita (KS) Eagle, pg. 2D:
Huie, who ran for the Legislature in 1994, talked of being called a “demoncrat” and said Broadfoot’s opponents called her an “evil witch.”

23 November 1997, Los Angeles (CA) Times, Life & Style, pg. E3:
Marilyn also likes to call the Democrats “the Demoncrats” for obvious reasons.

Google Groups: misc.survivalism
Newsgroups: misc.survivalism
From: (Gunner)
Date: 1999/12/29
Subject: OT- Demoncrats

Google Groups: alt.politics.clinton
Newsgroups: alt.politics.clinton
From: “Mike”
Date: 2000/07/22
Subject: Bush, the alleged Texas deficit, and the DEMONcRAT spin machine

Google Groups: alt.politics.clinton
Newsgroups: alt.politics.clinton
From: “Mike”
Date: 2000/02/10
Subject: DEMONcRATS trying to influence the Rep primary

16 August 2008, Washington (DC) Times:
Demon-crat values