The OED has launched an appeal for members of the public to help track down the origins of 40 words which feature in the dictionary but do not have a known origin. They are hoping that eagle-eyed readers will be able to settle disputes over the first usage of popular words and phrases.

Among the 40 mystery words are two terms the OED believe originated from Irish authors.

The word 'loo', a shortened term for lavatory, is believed to originate from James Joyce, who in Ulysses referred to a watercloset as a "waterloo".

Likewise, the term 'hoodie', meaning a jumper with a hood, is believed to have entered the lexicon only after appearing in Roddy Doyle's 1990 novel The Snapper. During a passage in Doyle's Dublin-based novel, two characters come into contact and one exclaims, "You're after ripping me hoodie."

Both words are currently credited to the Irish authors, but now the OED is seeking to find out whether the terms had been in use prior to being published in the two books. In a new series of the BBC2 show Balderdash & Piffle, to be broadcast this spring, the public will be called upon to suggest new theories for how these terms entered the dictionary.

'Loo' and 'hoodie' are just two of the common phrases that are puzzling OED chiefs. Among the other words and terms the public will be asked to help with are 'glamour model', 'plonker', 'wolf-whistle' and 'kinky'. All of these terms have entered common usage without any explanation of their origins.

The first recorded example of the term 'glamour model' is in an advert in The Times newspaper in 1981, from a business "looking for new faces for fashion, photographic and glamour modelling".

In the case of 'plonker', the OED records its first usage in the 1966 novel, All Neat In Black Stockings, by Jane Gaskell, although the term did not enter into popular usage until it was featured in the hit television show Only Fools and Horses.

However, according to language expert Diarmaid O Muirithe, the OED can place too much emphasis on when a term was first written down, as opposed to when it entered the language.

O Muirithe suggests that while terms such as 'hoodie' might not have been written down until recently, they may have been in popular usage for several years previously.

"In the case of 'loo', I doubt very much that originates from Joyce, " he told the Sunday Tribune. "That term comes from the French word for water or 'l'eau'. When throwing buckets of urine onto the street, the Scots used to shout "garde l'eau", which means 'watch the water'."

O Muirithe also cast doubt over whether Roddy Doyle was the creator of the word 'hoodie', saying that while Doyle may have been the first to write it down, the word is generally accepted to have originated in London.