Tosspot is a British

British people

The British are citizens of the United Kingdom, of the Isle of Man, any of the Channel Islands, or of any of the British overseas territories, and their descendants...

 slang

Slang

Slang is the use of informal words and expressions that are not considered standard in the speaker's language or dialect but are considered more acceptable when used socially. Slang is often to be found in areas of the lexicon that refer to things considered taboo...

 insult, which can mean, depending on the context, a drunkard, a masturbator, or an objectionable person.

The word is of Middle English

Middle English

Middle English is the stage in the history of the English language during the High and Late Middle Ages, or roughly during the four centuries between the late 11th and the late 15th century....

 origin, and, until recently, meant exclusively a person who drank heavily. Beer

Beer

Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

 or ale

Ale

Ale is a type of beer brewed from malted barley using a warm fermentation with a strain of brewers' yeast. The yeast will ferment the beer quickly, giving it a sweet, full bodied and fruity taste...

 was customarily served in ceramic pots

Pottery

Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...

, so a tosspot was a person who copiously 'tossed back' such pots of beer. The word "tosspots" appears in relation to drunkenness in the song which closes Shakespeare's Twelfth Night. The morality play Like Will to Like, by Shakespeare's contemporary Ulpian Fulwell

Ulpian Fulwell

Ulpian Fulwell was an English Renaissance theatre playwright, satirist and poet.He became a rector of Naunton in 1570 and became a part of St. Mary Hall, Oxford in 1578....

, contains a character named Tom Tosspot, who remarks that

"If any poore man have in a whole week earned a grote

Groat

Groat or Fuppence is the traditional name of an English silver coin worth four English pence, and also a Scottish coin originally worth fourpence, with later issues being valued at eightpence and one shilling.-Name:...

,

He shal spend it in one houre in tossing the pot".

This meaning is losing currency, as tosspot is now often used synonymously with 'tosser

Tosser

Tosser may refer to:* wanker, UK slang for masturbater* an echomail processing program in FidoNet...

' (or 'wanker

Wanker

Wanker is a pejorative term of English origin, common in Commonwealth and ex-Commonwealth countries, including Britain, Ireland, Australia, New Zealand, and South Africa. It initially referred to an onanist but has since become a general insult. It is synonymous with tosser.-Meaning:The term wanker...

') to mean literally a man who masturbates ('tosses' his penis), or by extension somebody who is obnoxious, irritating or ridiculous. This assumed meaning is because of the similarity with 'tosser' and with words like 'sexpot' which designate a person as a 'pot'. Dictionaries generally acknowledge both meanings of tosspot.

More recently, 'tosspot' has become synonymous with idiot. It is often used as an endearing term, as by wife to husband.