The word twat has various functions. It is a vulgar

Vulgarism

A vulgarism , also called scurrility, is a colloquialism of an unpleasant action or unrefined character, which substitutes a coarse, indecorous word where the context might lead the reader to expect a more refined expression.-See also:*Euphemism*Grotesque body*Ribaldry, scatology, toilet...

 synonym

Synonym

Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...

 for the human vulva

Vulva

The vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....

, but is more widely used as a derogatory epithet

Epithet

An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

, especially in British English

British English

British English, or English , is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere...

. The word may originate from Old Norse

Old Norse

Old Norse is a North Germanic language that was spoken by inhabitants of Scandinavia and inhabitants of their overseas settlements during the Viking Age, until about 1300....

 þveit meaning cut, slit, or forest clearing.

Historical usage

Robert Browning

Robert Browning

Robert Browning was an English poet and playwright whose mastery of dramatic verse, especially dramatic monologues, made him one of the foremost Victorian poets.-Early years:...

 famously misused the term in his 1841 poem "Pippa Passes

Pippa Passes

Pippa Passes is a dramatic piece, as much play as poetry, by Robert Browning. It was published in 1841 as the first volume of his Bells and Pomegranates series, in a very inexpensive two-column edition for sixpence, and next republished in Poems in 1848, when it received much more critical attention...

", believing it to be an item of nun's clothing:

Then owls and bats

Cowls and twats

Monks and nuns in a cloister's moods

Adjourn to the oak-stump pantry

Its meaning was in reality the same then as now, Browning's misconception probably having arisen from a line in a 1660 satirical poem, Vanity of Vanities:

They talk't of his having a Cardinalls Hat

They'd send him as soon an Old Nuns Twat

Another mistaken (or perhaps dialectal) use was in Edward Bulwer-Lytton's 1870 science fiction novel The Coming Race, in an apparent satire on Darwin

Charles Darwin

Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

:

Among the pithy sayings which, according to tradition, the philosopher bequeathed to posterity in rhythmical form and sententious brevity, this is notably recorded: "Humble yourselves, my descendants; the father of your race was a 'twat' (tadpole

Tadpole

A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...

): exalt yourselves, my descendants, for it was the same Divine Thought which created your father that develops itself in exalting you."

It is commonly thought that a "twat" is a noun to describe a pregnant goldfish

Goldfish

The goldfish is a freshwater fish in the family Cyprinidae of order Cypriniformes. It was one of the earliest fish to be domesticated, and is one of the most commonly kept aquarium fish....

 . However, this is disputed by some and may be an urban myth .

Modern usage

Although sometimes used as a reference to the female genitalia, the word twat is more often used in various other ways:

• As a derogatory insult, a pejorative meaning a fool
  Foolishness
  Foolishness is the lack of wisdom. In this sense it differs from stupidity, which is the lack of intelligence. An act of foolishness is sometimes referred to as a folly....
  
  , a stronger alternative to the word twit - 'He can be a complete twat' (often used in the UK)
• To hit something (or someone) hard or violently - 'Let's get out there and twat it!'

In August 2008, the publisher of a children's book, My Sister Jodie by Jacqueline Wilson, decided to reprint the word 'twat' as 'twit' in future editions of the novel so as not to offend readers or their parents.

In a radio interview on 29 July 2009, the leader of the British Conservative Party, David Cameron apologized for any offence caused after he used the word "twat" on live radio during a breakfast radio show interview on Absolute Radio:

"The trouble with Twitter, the instantness of it – too many twits might make a twat."

He attempted to play down the incident, and added: "I was doing a radio interview and I'm sure that people will understand that."