*Doylum* was a word commonly used in Leeds, Yorkshire, North of England, where I grew up in the 1960s/70s. It basically means *idiot* - "What a doylum!"

At the time I thought this was strictly a Leeds word, but a quick search online finds it is still used and appears to be very popular with fans of Newcastle United and Hartlepool football teams. What this says about their quality of players I really couldn't say.  

It also crops up on Yorkshire dialect sites, but so far I can't find any explanation of its origin. Does anyone have any ideas?  

Also, Hartlepool and Newcastle are some 75-100 miles from Leeds - does anyone know if the word has spread there in the last 40 years or has it always been used there? Someone suggested to me that it might come from Yiddish as there is a large Jewish population in Leeds, though this would only be relevant if it truly is a Leeds word.