CUNT:- Latin or Sumarian. What is a 'USELESS

From the Latin a CUNEUS is a wedge or triangular shaped figure: 'Birtannia in cuneum tenuatur' = Tacitus describing Britain as being narrowed in the shape of a wedge.
Hence CUNEOLUS is a little wedge. Now add on the Latin for a tunnel or underground burrow CUNICULUS, and the Romans arrived at the word CUNNUS meaning the Pudendum Muliebre (The female genitals) - the triangle with a hole in the middle!!
Latin does not have many words to differentiate ideas, it has plenty of verb forms to indicate action, hence the actual meaning of a word has to be derived from its usage, hence a word like CUNNUS was also used to mean a Prostitute - nothing derogatory, but purely to describe that profession when practiced by females.
In early Latin the Romans had the letter K, so it is very probable that these words were originally spelt with a K, the K later being dropped entirely in favour of using just the C.
Now in other parts of Europe/Scandinavia the K persisted so that the CUNNUS became the KUNTA or KUNTE; But in Britain, receiving Latin late in the day we started with CUNNE CUNTA and CUNTE, which by the 13th Century had definitely become CUNT.
Again not being used in a derogatory sense but used in place names like GROPECUNTE LANE and GROPECUNT STREET etc; Every medieval town probably had such a place close to the market square, and it merely told people what profession was carried out in that street. All such colourful names have long been ostracised by Political Correctness beginning in the late Georgian era.
By the time we get to the Victorians the word CUNT no longer describes a prostitute, but it is being used as a derogatory term for a female, but still retaining its original meaning of the female genitals note the difference between "You stupid cunt" and "Look at the cunt on her".

Now some linguists would have us go back to 3000 BC and the Sumarians saying that the word CUNT or CUNNUS derives from the CUNEiform writings. Records kept by the priestesses in the temples, hence the CUNIE were female scribes and they used the word KUNTA to describe women. And the Romans merely used the word CUNNUS to best describe a triangle or wedge as it resembles a woman between her legs, and then came back full circle to using the word to mean the woman herself, except this time as a prostitute and not as a scribe.

Now the crux of the matter is this, can someone tell me what does one mean when you call someone a 'Useless Cunt' - I know, that metaphorically a 'Useless Cunt' is a blithering dunderhead useless at what ever he/she is meant to be doing. But what does it mean in a literal sense? What is a useless cunt? I have never met one. Is it a nun married to God? Is it a medical deformity? Does it mean she is wearing a chastity belt? A cunt that has been overused and has to be used less? I await your suggestions.