What is an evening constitutional?
This usually, refers to a walk. In times past, wealthy people, would take "constitutionals," after supper, to aid digestion, to ponder, or chat together. Poorer people, might use the phrase, as slang, for visiting the out house, as this involved a short walk. The meaning relies some on context.
An Evening Constitutional. A constitutional, as defined by dictionary.com, is a mild walk or exercise taken to benefit one's health. In previous centuries, regal men and women would take constitutionals after their supper to help with digestion and to pontificate about the world around them.