A term of irony used for a very self-serving mother with very little inherent nurturing instinct and often a victim of psychosis and/or bipolar disorder. Her ugly and abusive behaviors often include but are not limited to: name calling, tyrannical micromanaging, violent rages, insensitivity, blaming her mistakes on everyone else, extreme vanity, envy of her childrens' talents disguised as "constructive" criticism, and a propensity towards often having a very phony and pleasant public facade. Joan Crawford was the prime example of such a mother.
Child #1: My mom grounded me for not making decent grades this quarter. She's an evil witch!
Child #2: Mommy Dearest is so distracted with her ego and ambitions that my grades only cross her mind when she remembers that they are going to reflect on her public image. THAT's evil witch dummy.
Child #1: Touché!
The term applied to a homosexual man who will knock you out and suck your dick.
"Man, I woke up with a knot on my head, and my pants around my ankles..."
"Sounds like you got a visit from Mommy Dearest"