Or, a kind of dessert that deeply resembles a loaf of bread only it's a lot sweeter, softer, and contains candied fruit... Which aren't actually fruits at all.
1) A person digs through trash and eats it. Observer says, "Dude, what a fruit cake!"
2) Why a 'fruit cake' is called a fruit cake is a mystery since it isn't really a cake, and it doesn't even have fruits inside.
The act of releasing green chunky diarrhea onto your partners face then, ejaculating on it, then punching him/her in the nose causing the colors to mix together to form a fruit cake like color.
John: I broke up with Emily last night.
Jorge: Why???
John: I gave her a fruit cake.