I’ve just got back from a good friend’s ‘stag do’ where the questions came up ‘why do we call someone about to get married a ‘stag’? And what do upcoming nuptials have to do with male deer?
It turns out that we have really been asking the wrong question; the question shouldn’t be about why someone about to get married is called a ‘stag’, but why every other male isn’t – it actually used to be that way. In the Proto-Germanic language, the same word, ‘stag’ was used to refer to any male animal. The word travelled to English with the Celts in around 500BCE.
Over time, the word has been replaced for describing males of most species, but the term stuck for deer and engaged humans.