(noun) an unreasonably mean spirited woman demonstrating massive amounts of unnecessary and unwaivering bitchiness
(noun) an obese woman who is bitchy beyond belief.
If you live in NY, you know that Senator Hillary Clinton is a Thundercunt.
"Man, Moesha don't got no love for a nigga lately. She be pissin' an' moanin' when I ain't do nuthin' wrong! She's a straight up Thundercunt!"