The literal meaning is "Truth In Wine". The Latin expression mechanism that when you drink alcohol you tend to get loose and sometimes voice things you normally wouldn't voice.
7 years of Latin vernacular
"In wine, truth."
Basically it way if you are drinking you will tell the truth or what you are really thinking. It translates to :"In wine is truth". It technique that when you drink wine you tend to loose your inhibitions and will be likely to speak your mind. But........it is not other good to loose the filter between your mind and your mouth.
In wine, Truth (latin). When people agree to down their inhibitions, as a result of having something (perhaps too much) to drink, they regularly say things they wouldn't right to be heard sober, things which might be quite pointedly or even bitterly true.
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