The phraseological turnover "to be under the fly" is used in the meaning of "to be drunk." In Russian literature, there is another form of this expression - "to be with a fly", "to hit a fly" or "crush".
There is no consensus among philologists regarding the origin of the idiomatic phrase “to be under the fly”. Different versions are being expressed.
Peter I and merchants
One of the hypotheses connects the origin of this expression with the era of Peter the Great. The tsar-reformer ordered to replace taverns with more "civilized" establishments - taverns, where visitors could not only drink, but also eat. To make potential customers more likely to prefer taverns rather than taverns, each visitor was supposed to pour the first glass for free.
How effective this "advertising campaign" turned out to be, history is silent, but it was too expensive for the owners of taverns. The merchants found a way out by ordering very small glasses - only 15 ml each - to the owners of glass factories, which significantly reduced the cost of free drinks.
Because of the small size of these glasses, they were nicknamed "flies", and "to be under the fly" or "crush a fly" meant "to drink a small glass of wine." These expressions were later used even among the nobility. One should not think that Eugene Onegin's uncle, who “looked out the window and crushed the flies,” spent his time exterminating insects - we are talking about drinking.
Other versions
There is another version linking the origin of the expression with utensils for alcoholic beverages. They say that a certain owner of a glass factory, having conceived to re-educate his drunken son, ordered to serve him wine and vodka only in a special glass specially made for him. The glass was made in such a way that the liquid poured into it created an illusion due to the play of light - it seemed that a fly was floating in the glass. However, the veracity of this story is questionable.
Some researchers believe that this is not about crystal dishes, but about flies. These insects do not cause sympathy for anyone: black, ugly, annoying, flying on rotten meat, half-decayed corpses and sewage. It is not surprising that the folk fantasy connected flies with dark forces, for example, the Belarusians had a saying “he has flies in his nose”, which meant “he is a sorcerer”. It was believed that a person could be persecuted by demons that take the form of flies. There was no doubt that a drunk was under the influence of demons.
The source of expression can be gamblers' jargon. In the 18th century. the card game Moche came to Russia from France, which by consonance was renamed into "fly", and then into "fly". Initially, "to be under the fly" meant "to be the winner", "to be lucky." The win was accompanied by a drink, which led to a change in value.
