Every day the BBC home page has a 'QI: fact of the day' (from the TV programme QI, which stands for 'quite interesting'). Earlier today the word under discussion was 'agelast' (there's already a new fact, I'm afraid, so the link won't take you to agelast).
Agelast (pronounced 'adj-ee-last') means 'one who never laughs'. According to the earlier QI fact box, if I remember correctly, the word derives from the name of the well-to-do Roman of the 2nd century BC, Crassus Agelastus, who was believed to have laughed only once in his life. Actually, I think it might have been the other way round - namely, Crassus was given the epithet Agelastus because he never, or hardly ever, laughed. The word 'agelast' is in the OED but the Dictionary says that it comes from the Greek word for 'not' tagged on to the word for 'laughing'.