dinner [ME] Our words dine [ME] and dinner are both from the same root, Old French desjeuner ‘to have breakfast’, which survives in modern French as déjeuner, ‘lunch’, and petit déjeuner, ‘breakfast’. The root was jëun ‘fasting’, which goes back to Latin jejunus ‘fasting, barren’ found also in jejune [E17th] which originally meant ‘without food’ and then ‘not intellectually nourishing’. The messy and unappetizing appearance of food set out for a dog is behind the expressions a dog’s dinner (or breakfast) [L19th], meaning ‘a poor piece of work, a mess’, and dressed up like a dog’s dinner, ‘wearing ridiculously smart or ostentatious clothes’, which dates from the 1930s.