An unborn child still in the womb. Specifically used in a derogatory manner when denouncing being the father of the child.
That bitch is crazy! I don't care how many times she said we fucked! That cunt runt is not mine!
Although mistakenly used today to describe all manner of women's play things and several races of newborn children, the Cuntrunt has its origins in 1940s Switzerland. A number of medical and theraputic revolutions were happening in this time, including operative LSD clinics, and exploits into "Parageinocology." The Cuntrunt was fashioned and sold by one such ParaGeino as a theraputic tool for pregnant women. Since they were so loose, the women required a little more girth in their massagers. Hence the first Cuntrunt was born from rather inexpensive wood and at first they were not properly shelacked, hence a horrible sliver scandal.
In present day the Cuntrunt has swept the globe and comes in many colors and materials, recognizable by their minimum girth of ten centemeters and their infant shape.
The Cuntrunt even crosses economic boundries, with poorer women using those dolls you fill with warm water, and the wealthier ones having a talented "Runtman" carve a ham into a baby shape, systematically heating and reheating for optimal sweatiness.
Why that's a fine Cuntrunt, who's the lucky mother?
A young girl or "shorty" who is sexually active during puberty.
Regular woman won't do it for me today, I'm gonna have to troll me the middle schools for a cunt runt.