nimrod
Nimrod is described in Genesis as being ‘a mighty hunter before the lord”. For those people who like to make allusions to the Bible, it was possible to refer to any hunter as a Nimrod. I doubt that it would stretch to a bloke going to the supermarket for meat so opportunities to use Nimrod in this sense are rare these days.
As well as hunting with skill and great success, Nimrod was responsible for the building of the Tower of Babel, an enterprise aimed at reaching Heaven, which ended badly as God intervened and made all the builders speak different languages so that they could not understand each other.
There is a citation in the OED for nimrod which dates back to 1933 but it is ambiguous. It might be a synonym for ‘idiot’ or it might be a reference to a man (who is madly in love) as a hunter. ‘The same old Nimrod. Won’t let her alone for a second.’
The next citation is in 1963 which is a bit of a jump. This one is lower-case nimrod and clearly means ‘an idiot’.
So how did the Americans get this new meaning? Google Ngram paints an interesting picture. The word spikes in frequency in the 1940s, drops away in the 1960s and then has a revival from 2000 on. The spike in the 1940s may have been caused by Bugs Bunny who, in a cartoon short called ‘A Wild Hare”, called Elmer Fudd a ‘poor little nimrod’.
One theory is that Bugs had in mind Elmer’s failed attempts to be a hunter and catch the hare. This was misunderstood by the audience who were not as familiar with the Bible as the cartoon writer was, and they took the meaning to be ‘an idiot’. This audience was huge and so the word gained frequency in that new sense.
The other possibility is, if we believe the 1933 citation, that there was a general use in American English of Nimrod as a reference to a stupid person and that the writer of Bugs Bunny was just using a bit of upmarket slang already in circulation. Either way, nimrod was given a huge boost by Bugs Bunny.
And now we in Australia have picked up nimrod. It has been around for a few years but has probably gained in frequency in recent years. I don’t think that anyone using it today is aware of its history in relation to either Bugs Bunny or the Bible.
PS. Because Nimrod Theatre comes to mind, I should say that it has nothing to do with the development of this item of slang. It was named that because it was in Nimrod Street, Kings Cross. What prompted the town planner’s flight of fancy, I don’t know.